The Stewart Mountain Dam is a concrete thin arch dam located 41 miles northeast of Phoenix, Arizona. The dam is 1,260 feet (380 m) long, 207 feet (63 m) high, and was built between 1928-30. The dam includes a 13,000 kilowatt (kW) hydroelectric generating unit that is operated by SRP (Salt River Project), an Arizona public utility. It is primarily operated during the summer months. The dam forms Saguaro Lake as it slows the passage of the Salt River in Maricopa County, Arizona. It was named after a ranch that used to be located nearby known as the Old Stewart Ranch.