1945 US Population | Statistics & Facts

US Population in 1945

The year 1945 marked an extraordinary moment in American history, representing both the culmination of World War II and the beginning of a transformative postwar era that would reshape the nation’s demographic landscape. The United States population in 1945 was estimated at approximately 139,928,165 residents, based on official government calculations that accounted for the extraordinary circumstances of wartime population distribution. This figure represented a 5.9 percent increase from the 1940 census count of 132,164,569 people, though the actual population dynamics were profoundly affected by the deployment of over 12 million military personnel, with millions stationed overseas in Europe, the Pacific, and other theaters of war. The 1945 US population estimate required complex methodological adjustments to account for armed forces overseas, making this one of the most challenging population assessments in American history due to unprecedented global military deployment and massive domestic population movements.

The 1945 population statistics captured America at a unique demographic crossroads, as the nation simultaneously experienced the strains of total war mobilization and the anticipation of postwar transition. Approximately 16.1 million Americans served in the military during World War II, representing 12 percent of the total population—an extraordinary mobilization that drew predominantly young men from civilian life and stationed them in military bases across the United States and battlefronts around the world. The 1945 demographic profile was fundamentally altered by this massive military mobilization, with profound gender imbalances in civilian populations, extensive internal migration to defense production centers, and the temporary evacuation of Japanese Americans to internment camps. The population count methodology for 1945 had to distinguish between total population including armed forces overseas and the civilian population actually present within continental United States boundaries, creating complexity in demographic analysis that would persist until servicemen returned home in late 1945 and 1946, triggering the baby boom that would define the next generation.

Interesting Stats & Facts About the 1945 US Population

Data Source: U.S. Census Bureau Historical Statistics 1789-1945; CDC Vital Statistics 1945; U.S. Census Bureau Population Projections 2025

The 1945 population of approximately 139.9 million (including armed forces overseas) or 132.0 million (continental United States only) captured America at an unprecedented historical moment when total war mobilization had transformed virtually every aspect of national life. The estimated 16.1 million Americans who served in the military during World War II represented the largest military mobilization in American history, drawing primarily young men aged 18 to 35 from civilian life and creating profound demographic disruptions including severe gender imbalances in many communities, labor shortages that drew millions of women into industrial employment, and massive population movements as workers relocated to defense production centers in California, Michigan, Texas, and other states with major war industries.

The birth rate of 19.6 per 1,000 population in 1945 reflected the continuing impact of wartime separations, with millions of couples unable to start families or expand existing families due to military service obligations that kept husbands overseas for years. This suppressed fertility during wartime would reverse dramatically in 1946 when servicemen returned home, triggering the baby boom that would add 76 million babies over the next two decades. The death rate of 10.0 per 1,000 (excluding military deaths overseas) remained relatively moderate for civilian populations, though when military combat deaths are included, the total American death toll from World War II exceeded 405,000 service members—representing one of the costliest conflicts in American history. The presence of over 19 million women in the workforce by 1945 represented a revolutionary social transformation, as “Rosie the Riveter” became a cultural icon symbolizing women’s essential contributions to war production in factories, shipyards, and aircraft plants across the nation. Comparing the 1945 population of 139.9 million to today’s projected 341.1 million as of January 2025, we observe an extraordinary 143.7 percent increase over 80 years, representing more than a doubling of the American population driven by the postwar baby boom, continued immigration, and increased life expectancy that would transform the United States into the world’s third most populous nation.

Male and Female Population Distribution in the US in 1945

Data Source: U.S. Census Bureau Population Estimates 1945; Historical Statistics of the United States 1789-1945

The gender distribution in the continental United States in 1945 revealed an extraordinary female majority, with 68,187,000 women comprising 51.6 percent of the continental population compared to 63,789,000 men representing 48.4 percent. This sex ratio of approximately 94.8 males per 100 females was dramatically skewed by the deployment of 7 to 8 million predominantly male service members stationed overseas in Europe, the Pacific, Asia, and other theaters of war, creating the most pronounced gender imbalance in American history. The female population exceeded the male population in the continental United States by approximately 4.4 million people, though this gap would close rapidly as servicemen returned home beginning in late 1945 and throughout 1946 following Victory in Europe (May 1945) and Victory over Japan (August 1945).

This wartime gender imbalance in 1945 created profound social and economic impacts across American communities, as women assumed responsibilities traditionally reserved for men including industrial production, farm management, business operation, and household headship while husbands, fathers, sons, and brothers served overseas. The gender dynamics of the 1945 US population reflected not only the temporary deployment of military forces but also the 405,000 American servicemen who would never return, having died in combat or from service-related causes, creating thousands of war widows and fatherless children. Among the continental population, gender ratios varied dramatically by age group, with young adult ages 20 to 35 showing the most severe male deficits due to military service concentration in these cohorts, while children and elderly populations maintained more balanced sex ratios. Understanding these gender distribution patterns in 1945 proved essential for understanding the immediate postwar period, when returning servicemen would trigger massive social changes including the marriage boom, baby boom, suburban expansion, and economic prosperity that would define the 1950s and 1960s, while also creating challenges for women who had gained economic independence and workplace experience during wartime but faced social pressures to return to traditional domestic roles.

Age Distribution of the US Population in 1945

Data Source: U.S. Census Bureau Historical Statistics; Population Estimates 1945

The age structure of the United States in 1945 portrayed a relatively young nation, with a median age of approximately 29.0 years reflecting the demographic impact of Depression-era fertility decline followed by modest wartime birth rates. The largest age cohort consisted of individuals aged 20 to 44 years, totaling approximately 52,680,000 people or 39.9 percent of the continental population—representing primarily those born during the 1900s through 1920s who had experienced childhood during the Roaring Twenties, adolescence during the Great Depression, and young adulthood during World War II. This massive generational cohort provided the workforce for war production, comprised the overwhelming majority of military personnel, and would become the parents of the baby boom generation in subsequent years.

The school-age and youth population aged 5 to 19 numbered approximately 32,450,000 or 24.6 percent, representing children and teenagers growing up during the Depression and war years who experienced rationing, Victory Gardens, air raid drills, and the absence of fathers serving overseas. The youngest cohort of children under 5 years totaled approximately 12,850,000 or 9.7 percent, reflecting birth rates suppressed by economic hardship during the Depression 1930s and wartime family separations during the early 1940s—this smaller birth cohort would contrast sharply with the baby boom beginning in 1946. The middle-aged population 45 to 64 years comprised 26,940,000 people or 20.4 percent, consisting primarily of those born in the late 1800s and early 1900s who had built careers during the prosperous 1920s, survived the Depression, and now managed wartime production or supported the war effort on the home front. Most notably, the elderly population aged 65 and over totaled only 7,056,000 or 5.3 percent—a remarkably small proportion compared to later decades, reflecting lower life expectancy, limited Social Security coverage (the program had begun only in 1935), and the absence of Medicare or comprehensive elderly care systems. This age distribution in 1945 created a highly favorable dependency ratio, with a large working-age population supporting relatively small youth and elderly populations, contributing to economic productivity despite wartime sacrifices. The demographic structure of 1945 would profoundly influence the postwar era, as this young, fertile population would drive the baby boom, suburban expansion, economic growth, and social transformation that would characterize American society throughout the 1950s and 1960s, fundamentally reshaping the nation’s demographic profile for generations to come.

Racial and Ethnic Composition in the US in 1945

Data Source: U.S. Census Bureau Historical Statistics 1789-1945; Population Estimates Based on 1940 Census

The racial composition of the United States in 1945 reflected a nation still overwhelmingly White, with approximately 118,214,870 White individuals comprising 89.6 percent of the continental population. This predominance reflected decades of restrictive immigration policies including the Chinese Exclusion Act (1882), immigration quotas favoring Northern European immigrants (1924 Immigration Act), and limited migration from non-European regions. The Black or African American population numbered approximately 13,040,000 people or 9.9 percent, concentrated primarily in southern states where Jim Crow segregation remained entrenched, though the Great Migration had relocated millions to northern and western cities seeking defense industry employment during the war years. World War II would prove a pivotal moment for African Americans, as military service, defense employment, and exposure to less segregated societies overseas would fuel the emerging civil rights movement that would transform American society over subsequent decades.

The Native American population totaled approximately 345,000 or 0.3 percent, representing survivors of centuries of displacement, disease, warfare, and forced assimilation policies that had devastated indigenous populations. Many Native Americans served with distinction in World War II, including the famous Navajo Code Talkers whose language provided unbreakable military communications in the Pacific theater. The Asian and Pacific Islander population numbered approximately 254,000 or 0.2 percent, including Chinese, Japanese, Filipino, and other Asian-ancestry Americans. The Japanese American population experienced one of the darkest chapters of American history in 1945, as approximately 120,000 individuals of Japanese descent—two-thirds of whom were American citizens—had been forcibly relocated to internment camps following Executive Order 9066 in 1942, representing a massive violation of civil liberties motivated by wartime hysteria and racial prejudice. Hispanic or Latino populations, while not separately enumerated in 1945 statistics, numbered several million concentrated in southwestern states including Texas, California, New Mexico, Arizona, and Colorado, with Mexican-American workers contributing significantly to wartime agriculture and industry. This racial and ethnic snapshot of 1945 captured America before the civil rights revolution, immigration liberalization, and demographic diversification that would transform the nation over subsequent decades, creating a society vastly more diverse and multicultural than the relatively homogeneous population of 1945 that emerged from World War II on the threshold of unprecedented social change.

State Population Rankings in the US in 1945

Data Source: U.S. Census Bureau State Population Estimates 1945; Historical Statistics

The state population rankings in 1945 demonstrated that New York remained the nation’s most populous state with approximately 13,479,000 residents comprising 10.2 percent of the continental US population, maintaining its historical dominance as the commercial, financial, and cultural capital of America centered on New York City’s role as the nation’s largest metropolitan area. Pennsylvania ranked second with 9,900,000 people or 7.5 percent, anchored by Philadelphia and Pittsburgh and representing the industrial heartland producing steel, coal, and manufactured goods essential to the war effort. California occupied third place with 9,590,000 residents representing 7.3 percent, positioned on the threshold of explosive growth that would propel it past Pennsylvania and New York to become the nation’s most populous state by 1964, driven by defense industries, aerospace development, entertainment production, and the postwar migration of millions seeking opportunities and pleasant climates.

Illinois ranked fourth with 8,025,000 people or 6.1 percent, dominated by Chicago’s role as transportation hub, manufacturing center, and commercial powerhouse, while Ohio held fifth position with 7,600,000 residents or 5.8 percent, another industrial giant producing automobiles, steel, rubber, and countless manufactured goods. Texas occupied sixth place with 7,030,000 people or 5.3 percent, beginning its transformation from primarily agricultural economy toward the oil, aerospace, and technology powerhouse it would become. Michigan ranked seventh with 5,840,000 residents or 4.4 percent, absolutely critical to war production as the “Arsenal of Democracy” where Detroit’s automobile factories converted to producing tanks, aircraft, and military vehicles. New Jersey, Massachusetts, and Missouri rounded out the top ten with 4,420,000, 4,315,000, and 3,785,000 people respectively, representing important industrial, commercial, and agricultural regions. This state population distribution in 1945 captured America at a demographic crossroads, with traditional northeastern and midwestern industrial states maintaining dominance while California and other Sunbelt states began attracting migration that would fundamentally reshape regional population balances, political power, and economic geography over subsequent decades as defense industries, air conditioning technology, and interstate highways enabled the great postwar migration that would define late 20th century American demographics.

Urban and Rural Population Distribution in the US in 1945

Data Source: U.S. Census Bureau Historical Statistics; Agricultural Statistics 1945

The urban-rural divide in the United States in 1945 revealed a predominantly urbanized nation, with approximately 88,927,000 people or 67.4 percent residing in urban areas defined as incorporated places of 2,500 inhabitants or more and certain densely populated unincorporated areas. This urban majority reflected decades of industrialization, agricultural mechanization, and economic opportunities concentrated in cities that had drawn millions from farms and small towns to urban centers throughout the late 19th and early 20th centuries. The rural population of 43,049,000 or 32.6 percent included both farm and nonfarm residents, with the farm population numbering approximately 25,200,000 or 19.1 percent—representing a dramatic decline from earlier eras when most Americans lived and worked on farms. World War II accelerated rural-to-urban migration as defense industries in cities offered high-paying employment that attracted millions of agricultural workers and their families to manufacturing centers.

The rural nonfarm population of approximately 17,849,000 or 13.5 percent consisted of small-town residents, rural residents employed in mining or forestry, and those living in unincorporated rural areas but not engaged in farming. The decline in farm population during 1945 reflected agricultural mechanization that enabled fewer workers to produce more food, supporting both the civilian population and millions of American and Allied military personnel worldwide. The wartime experience fundamentally altered rural America, as farm families experienced unprecedented prosperity from high agricultural prices, many rural youth served in military forces exposing them to wider world beyond their communities, and defense industries competed for agricultural labor driving wages upward and accelerating mechanization adoption. This urban-rural distribution in 1945 established patterns that would intensify dramatically over subsequent decades, with urban and suburban areas growing rapidly while rural populations declined both absolutely and relatively. The farm population would continue its long-term decline from 19.1 percent in 1945 to less than 2 percent by the 21st century, as agricultural productivity gains enabled tiny proportions of Americans to feed the entire nation and much of the world, fundamentally transforming the American landscape, economy, and society from its agricultural roots toward the urban and suburban nation that would emerge in the postwar era.

Labor Force and Employment in the US in 1945

Data Source: Bureau of Labor Statistics Historical Employment Statistics; War Production Board Records 1945

The American labor force in 1945 numbered approximately 53,860,000 civilian workers, with an extraordinarily low unemployment rate of 1.9 percent or 1,040,000 people—representing essentially full employment achieved through total war mobilization that absorbed virtually every available worker into defense production, agriculture, government service, or essential civilian industries. Beyond the civilian labor force, an additional 12,123,455 military personnel at peak mobilization represented Americans removed from civilian employment and serving in armed forces, creating acute labor shortages that fundamentally transformed American workplaces and social norms. The 19,570,000 women in the civilian labor force comprised 36.3 percent of all workers, representing an unprecedented level of female employment as “Rosie the Riveter” and millions of real women filled jobs in factories, shipyards, aircraft plants, and other industries previously reserved almost exclusively for men.

Manufacturing employment reached 15,524,000 workers or 29.4 percent of the employed civilian workforce, concentrated in war production including aircraft, ships, tanks, ammunition, weapons, and countless other military necessities that made America the “Arsenal of Democracy” supplying not only American forces but also British, Soviet, Chinese, and other Allied militaries worldwide. Agricultural employment totaled 8,580,000 or 16.2 percent, representing a continued decline from earlier decades yet remaining essential for feeding both civilian and military populations domestically and abroad. Government employment numbered 5,947,000 or 11.3 percent, expanded dramatically by wartime agencies managing production, rationing, price controls, and countless other aspects of the total war effort. The employment structure in 1945 captured American work life at an extraordinary moment of full mobilization, with virtually every able-bodied person either serving in military forces or contributing to war production and essential civilian needs. This wartime employment experience would have lasting impacts, as women proved capable of performing any job previously restricted to men, African Americans gained access to industrial employment and military service that would fuel civil rights demands, and workers enjoyed unprecedented prosperity from high wages and overtime pay that would create expectations for postwar living standards. The transition from war to peace beginning in late 1945 would pose enormous challenges as 12 million servicemen returned seeking civilian employment, millions of defense workers faced layoffs as war production ended, and the economy restructured from military to civilian output—challenges that many economists feared would trigger depression but that the nation successfully navigated through the GI Bill, pent-up consumer demand, and investment in housing, automobiles, and consumer goods that would drive postwar prosperity.

War Impact and Population Changes in the US in 1945

Data Source: Department of Defense Statistics; Census Bureau Wartime Population Studies; CDC Vital Statistics 1945

The war impact on the United States population in 1945 was profound and multifaceted, with 12,123,455 military personnel representing nearly 10 percent of the entire population serving in armed forces at peak mobilization—an extraordinary commitment that touched virtually every American family through sons, fathers, husbands, or brothers in military service. The human cost of 405,399 American military deaths during World War II (1941-1945) represented one of the costliest conflicts in national history, creating hundreds of thousands of grieving families, war widows, and fatherless children whose loss would shape the postwar generation. An additional 670,846 service members wounded in action returned home with physical and psychological scars requiring medical care, rehabilitation, and support that would continue for decades.

The forced relocation of approximately 120,000 Japanese Americans to internment camps represented one of the most shameful episodes in American history, as entire families were uprooted from homes, businesses, and communities on the West Coast and imprisoned in remote camps solely based on ancestry and wartime hysteria. The internal migration of over 15 million Americans during the war years represented the largest peacetime population movement in national history, as workers relocated to defense production centers in California, Michigan, Texas, and other states, while military personnel moved to training bases across the country before deployment overseas—this massive migration permanently reshaped regional population distributions and created boomtowns that would continue growing after the war. The birth rate of 19.6 per 1,000 in 1945 reflected continuing suppression of fertility by wartime family separations, though the rate would explode in 1946 as servicemen returned home, triggering the baby boom. The elevated marriage rate of 12.2 per 1,000 reflected both pre-deployment marriages as young couples rushed to marry before servicemen shipped overseas and reunions of couples separated by years of military service. The war experience of 1945 fundamentally transformed American society, breaking down regional, social, and racial barriers as Americans from diverse backgrounds served together, worked together, and fought together in common cause—experiences that would fuel demands for civil rights, gender equality, and social justice in the postwar era.

The 1945 US population of approximately 139.9 million (including armed forces overseas) has grown to a projected 341.1 million as of January 2025, representing an extraordinary 143.7 percent increase over 80 years. This remarkable growth trajectory reflects the immediate postwar baby boom that added 76 million babies between 1946 and 1964, continued immigration following liberalization of restrictive laws in 1965, and increased life expectancy from approximately 65 years in 1945 to over 78 years today. The demographic transformation extends far beyond simple numbers, as the overwhelmingly White (89.6 percent) and native-born population of 1945 has evolved into today’s multicultural, multiethnic society where non-White populations approach or exceed 40 percent in many regions and foreign-born residents comprise over 14 percent of the total population. The postwar generation born to 1945 parents created the baby boom that reshaped every American institution—overwhelming schools in the 1950s, colleges in the 1960s, housing markets in the 1970s and 1980s, and now retirement systems as this massive generation ages. The social transformations initiated during World War II—women’s workforce participation, African American civil rights activism, suburban expansion, and technology development—accelerated in subsequent decades, fundamentally altering American society in ways barely imaginable to citizens of 1945.

Looking ahead, the United States confronts demographic challenges vastly different from 1945, including rapid population aging as baby boomers retire, declining fertility rates now below replacement level, increasing dependency ratios as fewer workers support growing elderly populations, and continuing debates over immigration policy as the nation depends on immigration for population growth. The favorable demographics of 1945—young population, high fertility, minimal elderly population, and strong economic growth potential—have been replaced by 21st century challenges of supporting the largest elderly population in history, managing trillion-dollar retirement programs, addressing health care costs for aging populations, and maintaining economic vitality with slower population growth. Regional population patterns have shifted dramatically since 1945, with Sunbelt states gaining millions while Rust Belt states lose population, political power shifts from traditional industrial states to southern and western growth states, and metropolitan areas dominate as rural regions decline. The population of 1945 inherited a nation emerging from depression and war but poised for unprecedented prosperity and growth; today’s population inherits unparalleled wealth and technological advancement but faces challenges of inequality, polarization, climate change, and demographic aging that require wisdom, sacrifice, and collective action matching the Greatest Generation of 1945 who saved democracy, defeated fascism, and built the prosperous, powerful nation we inhabit today—a nation more than doubled in population, infinitely more diverse, technologically advanced beyond imagination, yet still grappling with ensuring liberty, justice, and opportunity for all Americans in the 21st century.

Disclaimer: This research report is compiled from publicly available sources. While reasonable efforts have been made to ensure accuracy, no representation or warranty, express or implied, is given as to the completeness or reliability of the information. We accept no liability for any errors, omissions, losses, or damages of any kind arising from the use of this report.

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