Edgewood is an unincorporated community and census-designated place in Harford County, Maryland, United States. The population was 25,562 at the 2010 census, up from 23,378 in 2000. Edgewood is located in southwestern Harford County. It is bordered to the west by Baltimore County, Joppatowne, to the north by Bel Air South, to the east by the …Edgewood is an unincorporated community and census-designated place in Harford County, Maryland, United States. The population was 25,562 at the 2010 census, up from 23,378 in 2000. Edgewood is located in southwestern Harford County. It is bordered to the west by Baltimore County, Joppatowne, to the north by Bel Air South, to the east by the Bush River, an arm of Chesapeake Bay, to the south by the Edgewood Arsenal portion of Aberdeen Proving Ground, and to the southwest by the tidal Gunpowder River, another arm of the Chesapeake.