Washington County is a county in Texas. As of the 2020 census, the population was 35,805. Its county seat is Brenham, which is located along U.S. Highway 290, 72 miles northwest of Houston. The county was created in 1835 as a municipality of Mexico and organized as a county in 1837. It is named for George Washington, the first president of the United States.

Brenham is a city in east-central Texas, United States, and the county seat of Washington County, with a population of 17,369 according to the 2020 U.S. census.