Big Flat Reservoir   Be the first to submit input for Big Flat Reservoir. If you have info on Big Flat Reservoir, Malheur County, Oregon please submit it here to improve this web site.          These outdoors activities are available near Big Flat Reservoir.   Public Lands Near Big Flat Reservoir: Malheur National Forest, Oregon, 22 miles away Unity Lake State Park, Oregon, 30 miles away   Hotels Near Big Flat Reservoir: Knights Inn Baker City, Baker City, 43 miles away Rodeway Inn Baker City, Baker City, 43 miles away Best Western Sunridge Inn, Baker City, 43 miles away Super 8 Baker City, Baker City, 43 miles away