Even though Austin's housing market is cooling, regional growth continues shifting. The area has two especially fast-growing counties, which just squeezed into the top 10 U.S. counties that added the most residents from 2024 to 2025, according to U.S. Census Bureau estimates that came out this spring.

Whether the data (between July 1, 2024, and July 1, 2025) is ranked by total new residents or percentage growth , Austin has counties in both top 10 lists. To calculate population growth, the Census Bureau takes into account births, new residents, deaths, and moved-away residents.

Austin's Williamson County ranked No. 9 by total residents added. It gained 23,814 residents, landing at 752,827. That’s a one-year growth rate of 3.2 percent. Folks who live in the area probably aren't surprised to hear this, as Williamson County, a.k.a. "Wilco," contains several very hot suburbs: Round Rock, Georgetown, Cedar Park, and Leander. These cities are constantly on national lists of the best suburbs to move to thanks to their affordability, cultural vibrancy, and mix of big- and small-city living.

Houston-anchored Harris County was at the top of the list. Over the one-year period, it gained 48,695 residents, or 1 percent, pushing its population over the five million mark.

The rest of the Texas counties in the overall top 10 numerically are:

• Second-ranked Collin County (Dallas area): Gain of 42,966 residents, with a July 1, 2025 total of 1,297,179. That's a one-year growth rate of 3.4 percent.
• Fourth-ranked Montgomery County (Houston area): Gain of 30,011 residents, with a July 1, 2025, total of 781,194. That’s a one-year growth rate of four percent.
• Eighth-ranked Fort Bend County (Houston area): Gain of 24,163 residents, with a July 1, 2025, total of 975,191. That’s a one-year growth rate of 2.5 percent.

When measuring by percentage, Caldwell County near Austin ranked No. 10. Caldwell County's population grew 4.2 percent to 55,150. That's 2,211 new residents. The county is to the southeast of Austin and most notably contains Lockhart, which draws tourists for barbecue and might have the next big music scene outside of the Texas capital. Technically, it is more associated with San Marcos than Austin, but both are part of the same metropolitan area.

Other counties in Texas saw even more growth by percentage:

• Second-ranked Waller County (Houston area), whose population climbed 5.69 percent, winding up at 69,858.
• Third-ranked Kaufman County (Dallas-Fort Worth area), whose population rose 5.7 percent to 209,235.
• Eighth-ranked Liberty County (Houston area), whose population rose 4.4 percent to 121,364.

On a percentage basis, no metro area in Texas appears among the 10 fast-growing metro areas. However, the state’s four major metros are among the 10 fastest-growing on a numeric basis:

• Houston: The metro area ranked first for growth on a numeric basis, adding 126,720 residents in just one year. The region’s population was slightly over 7.9 million on July 1, 2025, representing a 1.6 percent growth rate.
• DFW: The metro area ranked second for growth on a numeric basis, gaining 123,557 residents during the one-year period. Its population as of July 1, 2025, was nearly 8.48 million, representing a nearly 1.5 percent growth rate.
• Austin: The metro area ranked sixth for growth on a numeric basis, expanding by 53,796 residents. As of July 1, 2025, the region’s population was 2.62 million, with a 2.1 percent growth rate.
• San Antonio: The metro area ranked ninth for growth on a numeric basis, picking up 38,402 residents. The region’s population was 2.81 million on July 1, 2025, with a nearly 1.4 percent growth rate.

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Brianna Caleri contributed to this report.