Kyle is a city in Hays County, Texas, United States. Its population grew from 28,016 in 2010 to 45,697 in 2020, making it one of Texas' fastest-growing cities. It is part of the Greater Austin area. Kyle is in eastern Hays County and is bordered to the south by San Marcos and to the northwest by Mountain City. Kyle is 21 mi southwest of downtown Austin and 58 mi northeast of San Antonio on Interstate 35.