Grimes County is a county located in southeastern Texas, United States. As of the 2020 census, its population was 29,268. The seat of the county is Anderson. The county was formed from Montgomery County in 1846. It is named for Jesse Grimes, a signer of the Texas Declaration of Independence and early European-American settler of the county.

Anderson is a city and county seat of Grimes County, Texas, United States. The population was 193 as of the 2020 census. The town and its surroundings are listed on the National Register of Historic Places as the Anderson Historic District.