Jasper County is a county located in the U.S. state of Texas. As of the 2020 census, its population was 32,980. Its county seat is Jasper. The county was created as a municipality in Mexico in 1834, and in 1837 was organized as a county in the Republic of Texas. It is named for William Jasper, an American Revolutionary War hero.

Jasper is a city in and the county seat of Jasper County, Texas, United States. Its population was 6,884 at the 2020 U.S. Census, down from 7,590 at the 2010 U.S. Census. Jasper is situated in the Deep East Texas subregion, about 40 miles (64 km) west of the Texas-Louisiana state line. Jasper holds an annual Butterfly Festival the first Saturday in October to celebrate the migration of the monarch butterflies.