Brennan Reservoir   Be the first to submit input for Brennan Reservoir. If you have info on Brennan Reservoir, Crook County, Oregon please submit it here to improve this web site.          These outdoors activities are available near Brennan Reservoir.   Public Lands Near Brennan Reservoir: Cline Falls State Park, Oregon, 22 miles away John Day Fossil Beds National Monument, Kimberly - OR, 34 miles away   Hiking Trails Near Brennan Reservoir: Owl Creek Trail, Wheeler County, 14 miles away        1 hiking miles, 301 feet elevation difference Coffeepot Trail, Wheeler County, 16 miles away        1.8 hiking miles, 887 feet elevation difference Black Canyon Trail, Wheeler County, 16 miles away       8.1 hiking miles, 3351 feet elevation difference