The name Greenleaf was first applied to the community about 1885, and when a post office was established in the area in 1892, the same name was used.[2] The name may refer to the abundance of bigleaf maple trees in the area.[2] Greenleaf is also the name of a creek that flows into Lake Creek where the post office was first located.[2] The post office was moved in 1908 about 3 miles (5 km) down Lake Creek.[2] Greenleaf post office closed in 1987;[3] Greenleaf now has a Deadwood mailing address.[4]