The Piedra River (also known as El Rio De La Piedra Parada, Pedra, Rio, and Rio Piedre) is a river in the U.S. state of Colorado. It drains parts of Archuleta, Hinsdale, and Mineral counties along a mainstem length of about 40 miles (64 km). The river flows through a series of isolated box canyons, emptying into the San Juan River at Navajo Lake. Its name stems from the Spanish word, piedra, meaning rock.