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.
Quanah is 192 miles (309 km) northwest of Fort Worth and 8 miles (13 km) south of the Red River, which forms the Oklahoma-Texas state line. Copper Breaks State Park is 12 miles (19 km) south of the city.
Quanah was organized in 1884 as a stop on the Fort Worth and Denver Railway. The city is named for Quanah Parker, the last Comanche chief.
The county seat of Hardeman County was moved from Margaret to Quanah in 1890 after an acrimonious battle that contributed to the splitting off of the southern section of Hardeman County as Foard County. The courthouse, constructed in 1908, anchors what is now the historic downtown district. The courthouse was financed by a bond election approved by voters in 1906. The project architect was R.H. Stuckey of Chillicothe, Texas.