Population growth is slowing across most U.S. counties following a sharp decline in immigration, according to new Census Bureau data. International migration fell in nine out of 10 counties between 2024 and 2025 compared to the previous period. The remaining counties saw flat migration levels.
The decline particularly affects large population centers that typically serve as migration hubs. These counties often gain substantial numbers of international migrants while losing residents to domestic migration to other areas. With reduced international migration, many of these populous counties experienced diminished growth or actual population losses.