Immigration in 2024 drove the overall U.S. population growth to its fastest rate in 23 years as the nation surpassed 340 million residents. The Census Bureau changed how it counted immigrants last year by including more people who were admitted to the U.S. for humanitarian, and often temporary, reasons.

The largest urban counties in the United States continued to grow last year, primarily due to international migration, according to new population estimates from the US Census Bureau. Core counties in metropolitan areas such as Houston,