Mannheim is a historic home and former grist mill located at San Mar, Washington County, Maryland, United States.

The house is a 2-story, three-bay structure built of roughly coursed local limestone, with a one-story stone kitchen wing.

Also on the property is a large frame bank barn and a small board-and-batten service kitchen or wash house.

[2] It was listed on the National Register of Historic Places in 1979.

This article about a Registered Historic Place in Washington County, Maryland is a stub.