Anne Arundel County forms part of the Baltimore-Washington metropolitan area. It is named for Anne Arundell (1615-1649), a member of the ancient family of Arundells in Cornwall, England and the wife of CÆcilius Calvert, 2nd Baron Baltimore. Its county seat is Annapolis, which is also the capital of the state. In 2000, its population was 489,656, while in 2003 the population was estimated to have reached 506,620.
It is also located to the south of the city of Baltimore. According to the U.S. Census Bureau, the county has a total area of 588 square miles (1,523 km2), of which, 416 square miles (1,077 km2) of it is land and 172 square miles (445 km2) of it (29.25%) is water. It is located on the western side of Chesapeake Bay, with numerous rivers and tidal creeks indenting the shoreline.