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. 

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.

RankCounty2023-2024 Population Change,
Number of People1Harris County, Texas105,8522Miami-Dade County, Florida64,2113Maricopa County, Arizona57,4714Collin County, Texas46,6945Clark County, Nevada44,5866King County, Washington43,3987Cook County, Illinois40,0958Broward County, Florida34,6869Montgomery County, Texas34,26810Tarrant County, Texas32,79311Orange County, Florida32,38112Denton County, Texas31,38413Fort Bend County, Texas31,31414Mecklenburg County, North Carolina30,05715Bexar County, Texas29,54816Santa Clara County, California29,18817Wake County, North Carolina29,05018Polk County, Florida28,70619Pinal County, Arizona27,46720New York County, New York27,43521Riverside County, California26,38422Williamson County, Texas25,84023Los Angeles County, California25,34224Kings County, New York24,69425Palm Beach County, Florida24,574

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.

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.