Austin will have to make room for an up-and-coming Central Texas city that's bringing in a bigger proportion of high-income earners than most other U.S. cities in recent years: Killeen.

A new study by SmartAsset discovered Killeen's explosive growth has created a 146.2 percent jump in high-income households since 2021.

The report ranked 345 of the largest U.S. cities based on proportional high-income growth during the one-year span between 2021 and 2022, when the latest U.S. Census Bureau data is available.

Killeen ranked No. 4 in the nation with the highest growth of high-income households, which the study (and the IRS) defines as households earning $200,000 in income or more.

The study found that nearly 1,200 high income-earning households were added to Killeen's population in the time frame. They made up 1.3 percent of the population in 2021, and rose to 3.2 percent in 2022.

Killeen's popularity isn't just with wealthier movers. A 2023 SmartAsset study discovered Killeen had the best housing market in the country for first-time homebuyers.

"High-income households may have an outsized impact on local economies, which can put increased pressure on housing markets, shift demand for services and businesses, and tax base contributions," the report's author wrote. "Examining the rate of growth of this cohort allows us to identify potential up-and-coming alternatives to established areas of wealth."

Killeen has proven to be an attractive move for one demographic in particular: millennials. Killeen drew in 16,853 millennials in 2022, which represented 10.8 percent of its population.

The North Austin suburb of Round Rock ranked No. 55 in the U.S. with a strong 51.1 percent growth rate of high-income households since 2021. Although the percentage seems high, it only amounts to 1,722 households added during the one-year time frame. These households made up 8.8 percent of Round Rock in 2021, which rose to 13.3 percent in 2022.

Austin, on the other hand, fell far down the list as No. 172, with 14,128 high-income households added since 2021, or a 19.2 percent growth rate. High-income households had a far greater presence in the Texas Capital than its suburbs: 14.6 percent in 2021, and 17.4 in 2022.

The U.S. city that increased its proportion the most is Spokane Valley, Washington. Though it totaled 1,510 high-income households, those represented a massive 183.3 percent growth rate.

The top 10 cities adding the most high-income-earning households in the U.S. are:

• No. 1 – Spokane Valley, Washington
• No. 2 – Allentown, Pennsylvania
• No. 3 – Evansville, Indiana
• No. 4 – Killeen, Texas
• No. 5 – San Tan Valley, Arizona
• No. 6 – Springfield, Massachusetts
• No. 7 – New Haven, Connecticut
• No. 8 – Manchester, New Hampshire
• No. 9 – Jackson, Mississippi
• No. 10 – Palmdale, California