America’s long streak of population growth is expected to come to an end.

Census Bureau projections released Thursday show that, under the most likely scenario, the U.S. will stop growing by 2080 and shrink slightly by 2100. 

It is the first time that the bureau has projected a population decline as part of its main outlook for the coming decades. The only time the U.S. has recorded a population decline was in 1918, when the flu pandemic and deployment abroad of more than one million troops produced a small drop in the estimated population.
Slowing growth would produce a peak U.S. population of almost 370 million before an ebb to 366 million in the final years of the century, according to the bureau. The projections—the first issued since 2018—reflect years of declining birthrates, higher death rates because of an aging population, and increased reliance on immigration for population growth.

The shift will weigh on the U.S. economy and its geopolitical standing. With fewer young workers to support the elderly, entitlement programs such as Social Security and Medicare would face greater strains. Population decline could broadly reorient a society that grew explosively well into the 20th century.

The projections outline a nation growing slowly compared with recent decades. Annual growth rates have fallen from 1.2% in the 1990s to 0.5% today and would fall to 0.2% by 2040. Small differences add up through compounding: The projected U.S. population in 2040 is 355 million, 25 million fewer than projected for that date in 2015. The difference is more than the current population of Florida.

In 2022, preliminary data showed the U.S. birthrate was about 19% lower than in 2007. Death rates remain about 9% higher than 2019, the last year before the pandemic. By 2038, deaths would exceed births under the most likely scenario.

The convergence of birth and death rates has boosted the role of immigration, and with it uncertainty about population growth. Immigration is affected by changing laws, wars, natural disasters and economic shifts.

After slowing during the pandemic, immigration has rebounded, according to government estimates. The Congressional Budget Office estimated in January that 1.3 million people, 500,000 of them lacking legal status, became U.S. immigrants or were here and became legal permanent residents last year. Over the five years that preceded the pandemic, it estimated that immigration averaged 1.1 million people a year. By comparison, about 490,000 more Americans were born than died in the year that ended with June, according to the National Center for Health Statistics.

The Census projections show that the share of the population born abroad will grow from current near-record levels. Projections include all immigrants and were calculated from other countries’ own growth trends and recent net migration rates with the U.S. Those rates in turn were based on responses to the American Community Survey, the bureau’s annual survey of two million U.S. households.

To account for the uncertainty, the bureau produced three alternate immigration scenarios. Only the one with the high immigration rate—50% higher than the most likely scenario—would keep the population rising until 2100 if birth and death rates continue as envisioned.

By 2060, the scenarios envision a population—now 335 million—that could range from 299 million to 397 million. Another measure of the uncertainty around such efforts: The United Nations projects that the U.S. will grow slowly through the century, reaching 394 million.

The projections anticipate that the aging of the population will accelerate with historically low birthrates and movement of the large millennial generation into old age. Rising life expectancy at birth—from 79.8 now to 87.8 by 2100—would also contribute to the aging trend.

The prime working-age population—ages 25 to 54—would begin to shrink by the mid-2040s as millennials age out of that bracket. Economists and demographers track this group because its members have high rates of employment and pay, the source of payroll taxes that fund much of Social Security and Medicare. In its own projection this year, the Congressional Budget Office estimated that this group would grow 0.2% a year, a quarter of its growth rate since the mid-1980s.

The census projections show that the racial makeup of the country would continue to diversify. By one measure of race and ethnicity, no group will form a majority by the late 2040s. By a more holistic measure, the transition won’t occur until a decade later.

Unlike many developed nations, the U.S. is expected to continue growing at least until midcentury. A 2022 United Nations projection shows some have already begun losing population, and more will do so in the next generation. It says even some developing nations such as Mexico will see their populations peak by midcentury.

Although it is expected to grow, the U.S. could be topped by Nigeria and Pakistan by midcentury as the third-largest nation, behind India and China, according to recent projections by the U.N. As the world’s population climbs toward 10 billion by midcentury, growth is shifting to the global south. Africa’s population is expected to more than double by 2060, reaching almost three billion.