Big Basin Reservoir   Be the first to submit input for Big Basin Reservoir. If you have info on Big Basin Reservoir, Steens Mountains, Harney County, Oregon please submit it here to improve this web site.          These outdoors activities are available near Big Basin Reservoir.   Hiking Trails Near Big Basin Reservoir: The Beef Trail, Harney County, 4 miles away       5 hiking miles, 644 feet elevation difference