Pecos Spring is a spring, 1.1 miles (3 km) northeast of Sheffield, in Pecos County, Texas. It lies at an elevation of 2060 feet. Pecos Spring was emitted from the Edwards and associated limestones of the Edwards-Trinity (Plateau) aquifer. On March 7, 1924, it discharged 0.7 cubic feet per second but by August 17, 1943, that had been reduced to 0.5 cubic feet per second. By 1961, its flow had ceased.