Round Rock is a city located in the U.S. state of Texas within Williamson County of the Austin–Round Rock metropolitan area. As of the 2000 U.S. Census, the city had a total population of 61,136 (though a 2004 estimate placed the population at 82,040).

In 1851 A small community formed on the banks of Brushy Creek, near a large round rock located in the middle of Brushy Creek. This round rock marked a convenient low-water crossing for wagons, horses and cattle. The first postmaster called the community Brushy Creek, but in 1854 the small settlement was renamed Round Rock in honor of this now famous rock.The "round rock" is located on Chisholm Trail Street in the middle of Brushy Creek. After the Civil War, Jesse Chisholm began to move cattle from South Texas through Round Rock, on the way to Abilene, Kansas. The route he established, which crossed Brushy Creek at the round rock became known as the Chisholm Trail. Most of the old buildings, including the old Saint Charles Hotel are still there today. This historic area is now called "Old Town".

Round Rock is headquarters to Dell, Inc.

Round Rock is home to the Class AAA Pacific Coast League minor league baseball team Round Rock Express, which is owned by (and named for) Nolan Ryan.

Round Rock calls itself the Sports Capital of Texas.

Downtown Round Rock is the site of the gunfight and subsequent capture (then death) of the nineteenth-century American train robber, Sam Bass, by the Texas Ranger Division on July 19, 1878. The event is known locally as the "Sam Bass Shootout". Bass is buried in Round Rock Cemetery, located south of "Old Town" on Sam Bass Road.