Baltimore County (/ˈbɔːltɪmɔːr/ BAWL-tim-or, locally: /bɔːldəˈmɔːr/ bawl-da-MOR or /ˈbɔːlmər/ BAWL-mər) is the third-most populous county in the U.S. state of Maryland and is part of the Baltimore metropolitan area. Baltimore County (which partially surrounds, though does not include, the independent 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. As of the 2020 census, the population was 854,535.