Boulder is the county seat and most populous city of Boulder County and the 11th most populous city in the U.S. state of Colorado. Boulder is located at the base of the foothills of the Rocky Mountains at an elevation of 5,430 feet. The city is 25 miles northwest of Denver. Wikipedia

Round Rock is a city in the state of Texas within the Greater Austin, Texas metropolitan area and Williamson County. The 2013 census estimate places the population at 109,821. Wikipedia