The United States added just 1.8 million people between July 2024 and July 2025, growth of 0.5 percent, according to the Census Bureau’s Vintage 2025 estimates, released in the same year the agency recorded the slowest population growth since the early pandemic year of 2021. The number itself is unremarkable. What is remarkable is the reversal behind it: 2024 had been the fastest year of US population growth since 2006, driven by a surge in net international migration that has since collapsed by more than half in a single year.
What Is Changing in America’s Population?
The Census Bureau put the US population at 341,784,857 in its 2025 official estimate, up from the 331,449,281 recorded in the 2020 census. Growth of 0.5 percent for the year to mid-2025 sits well below the historical American norm; the Population Reference Bureau notes that US population growth has slowed markedly over the long run, from roughly 1.7 to 1.8 percent annually in the 1950s to about 0.5 percent in 2025, a trajectory the organization explicitly compares with Europe’s earlier and steeper slowdown, from around 1.0 percent in the 1950s to near zero by 2000 and slightly negative in the 2020s. The Census Bureau projects growth will slow further still, to just 0.2 percent, adding roughly 835,000 people in 2026, the smallest annual gain since the pandemic year of 2021.
America’s Population Is Aging
The 65-and-over share of the US population reached 18 percent as of 2023 estimates, up from a considerably smaller share in prior decades, reflecting both the aging of the roughly 76-million-strong Baby Boomer cohort into their senior years and rising life expectancy, which stood at 79.0 years overall in 2024, 76.5 years for men and 81.4 years for women.
The Congressional Budget Office’s January 2026 Demographic Outlook projects the total fertility rate at just 1.58 births per woman for 2026, declining further to 1.53 by 2035 and remaining near that level through 2055, well below the 2.1 replacement threshold required for a generation to fully replace itself.
US Fertility Rate Projections, CBO January 2026
| Year | Projected Total Fertility Rate |
|---|---|
| 2025 | 1.59 |
| 2026 | 1.58 |
| 2035 | 1.53 |
| 2055 | ~1.53 |
Fertility and Births Are Reshaping Population Growth
The Census Bureau’s 2025 demographic profile put the US birth rate at 10.6 per 1,000 population against a death rate of 9.1 per 1,000, a narrowing gap that reflects both declining births and rising deaths among an aging population.
The CBO’s central projection is direct about where this leads: deaths are expected to exceed births for the first time around 2030, at which point immigration becomes the sole source of any further US population growth, a threshold Europe’s largest economies, including Germany, Italy, and Poland, have already crossed in recent years.
Immigration Is Still Important, But It Is Not the Whole Story
Net international migration’s role in US population growth has shifted dramatically over the past two decades. For most of the early 2000s and 2010s, natural increase, births exceeding deaths, was the primary driver of American population growth.
Since 2021, that relationship has reversed: net international migration accounted for roughly 87 percent of US population growth by 2024, according to Census Bureau data reviewed by demographic researchers, a genuine structural departure from the earlier pattern.
That immigration-driven growth has itself now reversed sharply. The Census Bureau’s Vintage 2025 estimates recorded net international migration of approximately 1.3 million for the 2024-2025 period, down from 2.7 million the year before, a decline of more than half in a single year.
The Population Reference Bureau describes this as an “immigration cliff” that, combined with low fertility and an aging population, is pushing the United States closer to the demographic experience already underway across much of Europe.
US Net International Migration, Recent Years
| Period | Net International Migration |
|---|---|
| 2023–2024 | 2.7 million |
| 2024–2025 | 1.3 million |
| Projected annual average, 2025–2035 (CBO, LPR+ only) | 830,000 |
| Projected annual average, 2046–2055 (CBO, LPR+ only) | 870,000 |
The Congressional Budget Office’s central demographic scenario makes the stakes of this migration dependence explicit: without any immigration, the CBO projects the US population would begin shrinking as early as 2033, a conclusion driven by the combination of fertility rates projected to remain below replacement level for a generation and an aging population moving into peak mortality years.
The United States Is Becoming More Regionally Divergent
National-level growth figures obscure sharp regional variation that has become a defining feature of recent US demographic change, with growth increasingly concentrated in Sun Belt states while parts of the Northeast and Midwest experience stagnation or outright decline, a divergence detailed further in a companion analysis of state-by-state population trends published alongside this piece.
Internal Migration Is Rewriting the Population Map
Domestic migration between states continues to favor lower-cost, warmer-climate regions over the higher-cost coastal metropolitan areas that drove growth in earlier decades, a pattern that predates but has intensified through the pandemic-era remote work shift and subsequent return-to-office adjustments.
Changing Racial and Ethnic Composition
The Census Bureau’s ongoing demographic surveys track the population’s racial and ethnic composition using distinct categories for race, ethnicity, and Hispanic origin, definitions the Bureau revised for the 2020 census to allow more detailed self-identification than prior counts.
Longer-term composition trends reflect both differential natural increase and immigration patterns across groups, with the Bureau’s American Community Survey serving as the primary ongoing source for tracking these shifts between decennial censuses.
Household and Family Change
The interplay between falling fertility, delayed marriage, and rising longevity has been reshaping US household composition over recent decades, a trend the CBO’s demographic modeling incorporates directly into its fertility projections by tracking separate age-specific fertility rates for women under 30 and women 30 and older.
The CBO’s most recent projections show fertility for women under 30 continuing to decline, from 0.74 births per woman in 2026 to 0.60 by 2056, while fertility for women 30 and older is projected to rise modestly over the same period, from 0.85 to 0.93, a continuation of the multi-decade shift toward later childbearing already well documented across most high-income countries.
The Working Age Population
With deaths projected to exceed births by around 2030 and net migration having fallen sharply from its 2023-2024 peak, the size of the US working-age population going forward depends more heavily on immigration policy decisions than at almost any point in recent American demographic history.
The CBO’s central projection assumes net immigration of lawful permanent residents, refugees, and asylees averaging 830,000 annually from 2025 to 2035, rising to 870,000 annually from 2046 to 2055, alongside considerably smaller flows of other visa categories, assumptions that, if not realized, would directly affect projected labor force size and, by extension, Social Security and Medicare financing.
What America’s Demographic Future Looks Like
The CBO projects the US population will reach approximately 357 million by 2035 under its current central assumptions for immigration and fertility, though the agency’s own comparison of its January 2026 projections against its January 2025 projections shows the estimate has already been revised downward, reflecting both lower assumed fertility and reduced immigration flows relative to a year earlier.
The Population Reference Bureau frames the stakes plainly: if current trends in immigration, fertility, and aging persist without significant change, the United States could face outright population decline within the next decade, a scenario that would represent an unprecedented shift for a country that has never recorded a sustained peacetime population decline in its history.
Conclusion
The United States has, for most of its history, been a demographic outlier among wealthy nations, sustaining population growth that Europe’s largest economies stopped matching decades ago. The data from 2024 and 2025 marks the clearest sign yet that this gap is closing.
A sharp reversal in immigration, a fertility rate the CBO does not expect to recover, and a population aging into peak mortality years are converging on a trajectory that, if sustained, could bring the United States to its first sustained population decline within the coming decade, a threshold most of Europe crossed years ago.
Key Findings
- US population growth slowed to 0.5 percent for the year to mid-2025, the slowest pace since the pandemic year 2021, and is projected to fall further to just 0.2 percent in 2026.
- Net international migration fell from 2.7 million in 2023-2024 to approximately 1.3 million in 2024-2025, a decline of more than half in a single year.
- The Congressional Budget Office projects US fertility will fall to 1.53 births per woman by 2035 and remain near that level through 2055, and projects deaths will exceed births nationally by around 2030.
- Without any immigration, CBO’s central projection shows the US population beginning to shrink as early as 2033.
- Net international migration accounted for roughly 87 percent of total US population growth by 2024, a complete reversal from the early 2000s, when natural increase was the primary driver.
Frequently Asked Questions
1. What are the biggest demographic changes in the United States?
The most significant shifts are the sharp 2024-2025 decline in net international migration, a fertility rate now projected to remain well below replacement level through at least 2055, and an aging population moving toward a point around 2030 when national deaths are projected to exceed births.
2. Is America’s population aging?
Yes. The 65-and-over population share reached 18 percent as of 2023 estimates, driven by the aging Baby Boomer generation and rising life expectancy, now 79.0 years overall as of 2024.
3. Why is US population growth slowing?
Two forces are converging: a sharp decline in net international migration, from 2.7 million to approximately 1.3 million in a single year, and a persistently low fertility rate around 1.58 births per woman, well below the 2.1 replacement threshold.
4. Could the US population start shrinking?
The CBO’s central projection shows deaths exceeding births nationally by around 2030, making immigration the sole source of further growth; without any immigration, the agency projects population decline could begin as early as 2033.
5. What is the US total fertility rate?
The CBO projects US total fertility at 1.58 births per woman for 2026, declining to 1.53 by 2035 and remaining near that level through 2055, according to the agency’s January 2026 Demographic Outlook.
6. How much has US immigration declined?
Net international migration fell from 2.7 million in the 2023-2024 period to approximately 1.3 million in 2024-2025, a decline of more than half within a single year, according to Census Bureau Vintage 2025 estimates.
7. What is the US population in 2026?
The Census Bureau’s 2025 official estimate put the US population at 341,784,857, with growth of only about 835,000 people projected for 2026, the smallest annual gain since 2021.
8. How important is immigration to US population growth now?
Very important. Net international migration accounted for approximately 87 percent of total US population growth by 2024, a complete reversal from the early 2000s, when natural increase from births exceeding deaths was the primary driver.
9. What does the CBO project for the US population by 2035?
The CBO projects the US population will reach approximately 357 million by 2035 under its current central assumptions, though this figure has already been revised downward compared with the agency’s January 2025 projections.
10. How does US demographic change compare with Europe’s?
The Population Reference Bureau describes the current combination of an immigration decline, low fertility, and an aging population as placing the United States closer to the demographic experience already seen across much of Europe, where population growth slowed to near zero by 2000 and turned slightly negative in the 2020s.
Sources
- U.S. Census Bureau, Vintage 2025 National Population Estimates
- Population Reference Bureau: U.S. Population Growth Is Slowing to Near Zero (March 2026)
- Congressional Budget Office: The Demographic Outlook: 2026 to 2056 (January 2026)
- Congressional Budget Office: The Demographic Outlook: 2025 to 2055 (January 2025)
- Wikipedia: Demographics of the United States (citing Census Bureau data)
- BusinessStats: US Population 2015–2026 — Statistics & Facts (May 2026)
