The Austin-Round Rock-San Marcos metro area became the 25th largest in the country last year after continuing to rise in national rankings, boosted by the arrival of hundreds of thousands of new residents since the start of the decade.

The big picture

Entering the 2020s, the Austin-Round Rock Metropolitan Statistical Area ranked as the 28th most populated in the U.S. with 2.3 million residents. Following years of steady population increases, the region ranked 25th with an estimated 2.55 million residents as of July 2024, a nearly 11% increase, according to new census estimates released in March.

The Greater Austin totals cover Bastrop, Caldwell, Hays, Travis and Williamson counties.The Austin-Round Rock area grew by between 2.33% and 3.02% annually from 2020 through 2024, with the largest jump coming between 2021 and 2022. A total of 267,251 residents were added since 2020, most recently with an estimated 58,019 person increase from 2023 to 2024, census estimates show.

The changes over the four-year span were largely due to migration, with an estimated 132,535 new arrivals from within the U.S. and 71,200 internationally. The area also saw a more than 63,000 person population increase due to "natural change," or births minus deaths, according to the census data.Despite those gains, the pace of Central Texas' growth has slowed slightly from the second-fastest as of 2023 to the fourth-fastest in 2024. Austin Planning Director Lauren Middleton-Pratt attributed that to how people are moving to the region from both inside and outside the U.S.

"Domestic migration to Austin is the lowest we’ve seen in the last 15 years while international migration figures are at an all-time high," she wrote in a March 13 memo. "International migration is also driving the growth in several of the other high-ranking metros, including Houston and Orlando. Domestic migration, which typically makes up close to 60% of all growth in the Austin area, accounted for just under a quarter of our growth in 2024."

Zooming in

Within the five-county Austin-Round Rock-San Marcos metro, Travis County remains the largest by several hundred thousand residents, although it's growing at a slightly slower rate than its neighbors. It's also the fifth largest in Texas.The county's population passed 1.36 million in 2024, nearly double Williamson County's 727,480 and well above Hays, Bastrop and Caldwell counties, which are each home to less than 300,000 people, according to the new census data.

However, Caldwell County ranked as the ninth-fastest growing nationwide out of counties with 20,000 people or more with a 4.6% annual growth rate, Middleton-Pratt said. Travis County ranked the slowest in the region with a 1.2% rate, while the other three counties fell between 3.4%-3.7% annual growth.

After the March release of data for metro areas and counties, more detailed census estimates for city and town populations is expected in May.