The Owyhee Project lies west of the Snake River in Malheur County, Oregon, and Owyhee County, Idaho. The key feature is the Owyhee Dam, on the Owyhee River about 11 miles southwest of Adrian, Oregon. The dam is a concrete, thick-arch structure which was designed to carry about three-fourths of the water load by arch action, and the remainder by gravity action. The dam rises 417 feet above foundation in the river section and, at the time of its construction (1928-1932) was the world's highest dam. Owyhee Dam became a proving ground for theories being developed to assist with the design and construction of Hoover Dam, whose unprecedented size, 300 feet higher than Owyhee, required totally new construction methods.This 52-mile-long, 13,900-acre reservoir is located approximately 50 miles south of Ontario. Vehicle access is limited to the dam gravel road access to Leslie Gulch, Dry Creek, and Red Butte. Owyhee Irrigation District operates a visitor information center located in the historic construction office below the dam. Displays primarily focus on construction of Owyhee Dam and Irrigation Project. The facility is handicap accessible. Available fish species include largemouth bass, smallmouth bass, crappie, rainbow trout, brown bullhead, and yellow perch. Season open year-round. For reservations call 1-800-452-5687.

South from Ontario, Oregon on State Highway 201. County road to dam.