Pecos (/ˈpeɪkəs/ PAY-kəs) is the largest city in and the county seat of Reeves County, Texas, United States. It is situated in the river valley on the west bank of the Pecos River at the eastern edge of the Chihuahuan Desert and the Trans-Pecos region of west Texas and near the southern border of New Mexico. The population was 8,780 at the 2010 census. The city on January 24, 2012, had just appeared on Forbes 400 as the 2nd fastest-growing small town in the country.