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]
38°19′44″N 76°27′49″W / 38.32889°N 76.46361°W
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]
38°19′44″N 76°27′49″W / 38.32889°N 76.46361°W