Schertz is a city in Guadalupe, Bexar, and Comal counties in the U.S. state of Texas, within the San Antonio–New Braunfels metropolitan a…Schertz is a city in Guadalupe, Bexar, and Comal counties in the U.S. state of Texas, within the San Antonio–New Braunfels metropolitan area. The population was 42,002 at the 2020 census, up from 31,465 at the 2010 census. Schertz was settled by Alsatian emigrants in the 1800s.