Twin Buttes Reservoir is an artificial lake located about 6 mi (9.7 km) southwest of the city of San Angelo, Texas, and immediately upstream from Lake Nasworthy. With the financial support of the Upper Colorado River Authority, construction on Twin Buttes Dam to form the reservoir was completed in 1963. The dam is an unusual one – it dams the Middle and South Concho Rivers separately; a stabilization channel runs between the two sides of the lake.