Twinbrook is a large residential subdivision in the city of Rockville, Maryland. The name Twinbrook or Twin-Brook came from the four developers, Joseph L. Geeraert, Roland Simmon, Wesley Sauter, and Donald Gingery, who originally established the new subdivision on October 18, 1946. The name was a reference to the two streams that traversed the original 200 acres of the development, both eventually feeding into Rock Creek, which is the namesake feature of Rock Creek Park, a unit of the National Park Service.