The Hyder Valley is a 20-mile (32 km) long valley section of the Gila River Valley at Hyder on the Gila River. The valley is located north of Gila River in southwest Arizona in the northwestern Sonoran Desert. The Park Valley, which crosses the Gila borders to the southwest; the Hyder Valley is the access route to the Dendora Valley northeast which is on the western border of the Painted Rock Dam and Reservoir.