Immigration to the United States in 2024 propelled the nation’s population growth to its fastest rate since 2001, pushing the total number of residents past 340 million, according to the U.S. Census Bureau.

The Census Bureau announced on Dec. 19 that the population of the United States grew by nearly 1 percent in 2024, marking a stark contrast with the record low 0.2 percent in 2021, a year defined by strict pandemic-related travel restrictions.

Net international migration accounted for 84 percent—or 2.8 million—of the nation’s 3.3 million population increase this year, according to the Census Bureau’s count.

Natural increase—births outnumbering deaths—contributed 519,000 to the population growth, an improvement from the historic low of 146,000 in 2021 but still lagging behind levels seen in prior decades.

“What stands out is the diminishing role of natural increase over the last five years, as net international migration has become the primary driver of the nation’s growth,” Kristie Wilder, a demographer at the Census Bureau, said in a statement.

The Census Bureau’s figures do not include illegal immigrants, which excluding gotaways amounted to roughly 2.9 million additional entrants into the United States in fiscal year 2024. According to estimates, the total illegal immigrant population in the United States ranges from about 11 million to 21 million.

However, for the first time, this year’s Census Bureau numbers include people admitted under humanitarian parole. This is a temporary entry permit process for foreign nationals who are normally inadmissible to the United States but have compelling reasons to enter. Humanitarian parole has been in place for many decades, with the Migration Policy Institute, a Washington-based research organization, recently estimating that over 5.8 million people were admitted under various humanitarian policies from 2021 to 2024.

President-elect Donald Trump, who has railed against illegal immigration and has vowed to implement mass deportation, has also expressed skepticism about humanitarian parole, alleging on the campaign trail that there has been “outrageous abuse of parole.” During his first term, Trump sharply reduced the number of refugees allowed into the United States and has promised to push a “merit-based immigration system that protects American labor and promotes American values.”

Population growth was not uniform across the country, the Census Bureau data showed. The South emerged as the fastest-growing region, adding 1.8 million residents—more than all other regions combined. Texas and Florida led the region, with respective gains of 563,000 and 467,000 people. The District of Columbia, however, had the highest growth rate at 2.2 percent.

The West saw a gain of 688,000 residents, driven largely by international migration, while the Northeast and Midwest experienced smaller increases of 435,000 and 410,000 residents, respectively. Domestic migration remained a challenge for many areas, with California, New York, and Illinois posting the largest net losses.

Despite these trends, the Census Bureau noted that 47 states and the District of Columbia saw population increases, with Texas, Florida, and California leading in numeric gains.