Hardeman County is a county located in the U.S. state of Texas. As of the 2020 census, its population was 3,549. The county seat and largest city is Quanah. The county was created in 1858 and later organized in 1884. It is named for two brothers, Bailey Hardeman and Thomas Jones Hardeman, early Texas politicians and legislators. Hardeman County was one of 46 prohibition or entirely dry counties in the state of Texas until November 2006, when voters approved referendums to permit the legal sale of alcoholic beverages for on- and off-premises consumption.

Quanah is a city in and the county seat of Hardeman County, Texas, United States. As of the 2010 census the population was 2,641, down from 3,022 at the 2000 census.