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Johnstown, Maryland 
Summary
Johnstown is an unincorporated community in Calvert County, Maryland, United States.[1] The historic Preston-on-the-Patuxent house was listed on the National Register of Historic Places in 1974.[2]
References edit
- ^ "Geographic Names Information System". Johnstown (Populated Place). U.S. Geological Survey. January 29, 2009.
- ^ "National Register Information System". National Register of Historic Places. National Park Service. April 15, 2008.
38°19′44″N 76°27′49″W / 38.32889°N 76.46361°W