Hemphill County is a county located in the U.S. state of Texas. As of the 2010 census, its population was 3,807. The county seat and only incorporated community in the county is Canadian. The county was created in 1876 and organized in 1887. It is named for John Hemphill, a judge and Confederate congressman. Hemphill County is one of 30 prohibition, or entirely dry, counties in the state of Texas.