Reagan County is a county located on the Edwards Plateau in the U.S. state of Texas. As of the 2010 census, its population was 3,367. The county seat is Big Lake. The county is named in honor of John Henninger Reagan (1818-1905), who served as postmaster general of the Confederate States of America and also as a U.S. Senator, U.S. Representative, and first chairman of the Railroad Commission of Texas.