On average, U.S. counties grew by 1,000 people from 2023 to 2024. 

But the level of population growth varied widely from place to place. 

This chart, via Visual Capitalist's Jenna Ross, in partnership with BGO, shows the fastest-growing counties. 

Ranking the Largest Population Increases in U.S. Counties

Using the latest data available from the U.S. Census Bureau, here are the counties that had the largest population growth measured in number of people.

Harris County, which includes Houston and neighboring communities, had by far the biggest population growth. The primary driver of the county’s growth was international migration. On a domestic basis, more U.S. residents moved out of Harris County than those that moved into the area. 

While international migration was the biggest contributor to population growth in most areas, some counties bucked the trend. Domestic migration drove the bulk of population growth in Montgomery County, Denton County, and Williamson County in Texas, along with Polk County, Florida and Pinal County, Arizona.

The only county on the list to see a bigger boost from the natural change in population (births minus deaths) compared to net migration was Kings County, New York.

Preparing for Larger Populations

In general, population growth was concentrated in counties that already had large populations. One challenge of growing populations can be ensuring there is sufficient housing for all of the new residents. 

To meet rising demand, BGO is expanding its investment in high-quality multi-family and build-to-rent communities across fast-growing Sunbelt and Western U.S. markets. This includes Phoenix in Maricopa County—now the third fastest-growing county in the country—as well as residential properties in other population growth hubs like Miami-Dade and King County.