Harford County is located in the U.S. state of Maryland. As of the 2020 census, the population was 260,924. Its county seat is Bel Air. Harford County is included in the Baltimore-Columbia-Towson, MD Metropolitan Statistical Area, which is also included in the Washington-Baltimore-Arlington, DC-MD-VA-WV-PA Combined Statistical Area.

Havre de Grace (listen), abbreviated HdG, is a city in Harford County, Maryland, United States, situated at the mouth of the Susquehanna River and the head of Chesapeake Bay. It is named after the port city of Le Havre, France, which in full was once Le Havre de Grâce (French, "Harbor of Grace"). The population was 12,952 at the 2010 United States Census. In 2014, the city was honored by Smithsonian magazine as one of the 20 best small towns to visit in the U.S.

Towson () is an unincorporated community and a census-designated place in Baltimore County, Maryland, United States. The population was 55,197 as of the 2010 census. It is the county seat of Baltimore County and the second-most populous unincorporated county seat in the United States (after Ellicott City, the seat of nearby Howard County, southwest of Baltimore).

Baltimore County is the third-most populous county in the U.S. state of Maryland and is part of the Baltimore metropolitan area. Baltimore County (which surrounds, though does not cover, the City of Baltimore) is part of the Northeast megalopolis, which stretches from Northern Virginia northward to Boston. Baltimore County hosts a diversified economy, with particular emphasis on education, government, and health care. The county is home to multiple universities, including Goucher College, Stevenson University (formerly Villa Julie College), Towson University, and University of Maryland, Baltimore County.