The South drove most US population growth, but the South's growth engine is now slowing down

For sixty years the South has been the engine of American population growth but new Census Bureau estimates suggest that engine is throttling down, and fast.

The clearest single number is Florida's. In the year ending July 2022, 310,892 more Americans moved into Florida from other states than left it. In the year ending July 2025, that figure was down to 22,517. Domestic migration into the country's signature growth state fell 93 percent in three years.

We pulled the Census Bureau's state population estimates to check the numbers behind a recent Brennan Center analysis making this argument.

Five states, three-fifths of American growth

Between 2020 and 2025, the United States added about 10.2 million people. The South accounted for 7.4 million of them, roughly 72 percent of all national growth.

Within the South, growth is remarkably concentrated. Florida, Texas, Georgia, North Carolina, and South Carolina together added 6.1 million people. That is 82.9 percent of the entire South's growth, and 59.8 percent of the growth of the whole country. Five states out of fifty produced three-fifths of American population growth this decade.

But those five are where the slowdown is now showing up.

Both of Florida's growth engines are cooling at once. Domestic migration is down 93 percent from its peak, and arrivals from abroad are down 46 percent from theirs. Florida's annual growth rate fell from 2.64 percent in 2021-22, the fastest in the nation, to 0.85 percent in 2024-25.

Florida has almost no cushion, because it records more deaths than births every year. Its natural change has been negative for the entire period. When migration stops, Florida's growth stops.

Texas has a floor that Florida doesn't

Texas shows the same migration pattern with a very different outcome. Domestic migration fell from 218,840 in 2021-22 to 67,299 in 2024-25, a 69 percent drop, and international migration fell from 354,864 to 167,475 in a single year.

But Texas adds roughly 157,000 people a year through births outpacing deaths, and that number has been remarkably steady. It has the second-youngest population in the country after Utah, which we found when mapping the oldest and youngest states. So while Florida's growth rate collapsed by two-thirds, Texas slowed from 1.84 percent to 1.25 percent.

Georgia sits between them: domestic migration fell from 79,102 to 27,333, roughly a two-thirds drop, cushioned by a relatively young population. North Carolina and South Carolina have held steadier, because both draw most of their growth from domestic migration that has stayed comparatively level, with South Carolina increasingly playing the retirement-destination role Florida once monopolized.

What it means for House seats

The Brennan Center projects the South gaining a record nine congressional seats after the 2030 census, which would give the region nearly 40 percent of the House.

We tested the direction using the official apportionment formula. Applying equal proportions to the 2025 population estimates, the South would gain four seats today, Florida and Texas picking up two each, with no southern state losing any. That would leave the region with 168 of 435 seats, or 38.6 percent.

So the direction is confirmed and the magnitude depends on the next five years. Nine seats assumes growth continues; four is what the numbers support right now. Either way the South keeps gaining, and the states losing seats are California, New York, Illinois, Minnesota, Oregon, and Rhode Island. We walk through how that machinery works in how the census shapes American politics.

Who is driving the growth

The Brennan Center's other finding is that people of color now account for all of the South's population growth, and that the white population declined in absolute terms in 10 of the region's 15 states, including Florida, Georgia, Texas, Louisiana, and Mississippi. That is drawn from the Census Bureau's race and ethnicity estimates released this summer, and it marks a change from earlier in the decade, when the South was one of only two regions where the white population was still growing.

The analysis goes on to argue that these communities may not gain representation proportional to their growth, citing the Supreme Court's decision this year in Louisiana v. Callais and subsequent redistricting activity across several southern states. The Brennan Center is a legal advocacy organization with a longstanding position on voting rights, so that conclusion is its argument rather than a finding in the census data. The population figures underneath it are straightforward Census Bureau estimates, and they are accurate.

The demographic point stands on its own. The South's growth is slowing toward the national norm, its remaining growth is coming almost entirely from people of color, and its share of national political power is still rising. Those three things are happening simultaneously.

Sources

Population, migration, and natural change figures are CensusEasy calculations from the U.S. Census Bureau Vintage 2025 state population estimates (NST-EST2025-ALLDATA), covering July-to-July periods. The apportionment projection applies the equal proportions method in federal law to those 2025 estimates across 50 states and is an illustration of current populations, not a forecast of 2030. The nine-seat projection, the white population findings, and the redistricting analysis are from the Brennan Center for Justice. Regional definitions follow the Census Bureau's South region.