A recent immigration surge brought newcomers to every state this year, helping to offset a continued drop in U.S. births while contributing to a national upswing of about 3.3 million new residents, according to new U.S. Census Bureau estimates.

Texas and Florida continued to dominate state population growth, together adding more than 1 million people from mid-2023 to mid-2024 and making up almost a third of the nation’s population increase. The state numbers include births, deaths, immigrants and residents moving from other states.

Nationally, this year’s population growth was up from the 2.8 million increase in 2023 and the 1.9 million boost in 2022, according to state population estimates released Thursday.

The population jump — the largest single-year increase since 2001 — was buoyed by a 21% increase in net immigration.

Immigration has become a more significant factor in population changes, making up all or almost all the growth for 18 states in every part of the country this year, according to an analysis of the data by William Frey, a demographer for the Brookings Institution, a left-leaning think tank.

“This points up the importance of immigration, not just to a couple of big states but to a broad swath of our country,” Frey said. “It’s going to be very welcome in a lot of places that would not be gaining many people or [would be] losing people because of lower fertility and higher deaths.”

Immigration grew in every state, ranging from an increase of about 69,000 people in Florida and California and 57,000 in Texas, down to a few hundred in Montana and Wyoming. The growth in the immigrant population ranged from 19% in Alaska to 36% in Montana.

California and Illinois were among states that had lost residents earlier in the decade, and their growth over the past year could help both stem expected losses in congressional representation after the next nationwide census in 2030.

If the growth continues, it would trim California’s loss to three seats in the U.S. House of Representatives instead of four, and Illinois could lose one seat instead of two, said Kimball Brace, a Virginia-based redistricting expert.

Florida, where growth has slowed slightly, could gain one fewer congressional seat than predicted — three instead of four, he said.

“Clearly immigration is coming into play — a couple years ago you had people talking about California going off the deep end [with population loss] and now it doesn’t look so deep,” said Brace, president of political consulting firm Election Data Services Inc.

California ranked third in the number of new residents from July 1, 2023, to July 1, 2024, according to census estimates, with a gain of about 233,000, thanks to both immigration and people moving in from other states. The Golden State was followed by North Carolina (165,000) and New York (130,000). Illinois grew by about 68,000 and Louisiana by about 9,700.

Florida and Texas also were the leaders in percentage change, growing about 2% in that year, followed by Utah (1.8%), South Carolina and Nevada (both up 1.7%), and Idaho and North Carolina (both up 1.5%).

Only three states had population losses for the year, of a few hundred people each: West Virginia, Vermont and Mississippi.

In Texas, the cities of Houston, Austin and Dallas added the most new housing last year — almost 40,000 new units among them — and are likely to be the centers of new population growth, according to a state report in November. Collin County, a Dallas suburb, is also one of the state’s fastest growing areas, with more than 16,000 new housing units added last year and almost 64,000 since 2020, according to the report.

Florida’s recent growth was concentrated in Jacksonville, Port St. Lucie, Miami, Tampa and Orlando, according to a state report this year.

A surplus of births over deaths helped most in New York, California, Pennsylvania, Ohio and Michigan.

New York City has built more housing, which helped stem net losses from people moving away, said Jan Vink, a senior extension associate at Cornell University’s Program on Applied Demographics.

That’s encouraging news for the state’s future, Vink said. In November, the university estimated that New York’s population could shrink by as much as 2 million people over the next 25 years because of low fertility rates and aging, unless those losses are offset by new arrivals in the form of immigration or people moving from other states.

Texas, the Carolinas, Florida and Tennessee had the largest numbers of new residents moving in from other states, though the numbers were down in all those states from the previous year as high interest rates and housing prices led more people to postpone moves.

Stateline, a States Newsroom affiliate, produced this report.