Complex sentence: Lake Roosevelt National Recreation Area is a U.S. National Recreation Area of the National Park Service that encompasses the long Franklin D. Roosevelt Lake between Grand Coulee Dam and Northport, Washington, in eastern Washington state.
Split into simpler sentences: Lake Roosevelt National Recreation Area is a U.S. National Recreation Area under the supervision of the National Park Service. It encompasses the long Franklin D. Roosevelt Lake between Grand Coulee Dam and Northport, Washington, in eastern Washington state.