Anne Arundel County, also notated as AA or A.A. County, is located in the U.S. state of Maryland. As of the 2020 United States census, its population was 588,261, an increase of just under 10% since 2010. Its county seat is Annapolis, which is also the capital of the state. The county is named for Anne Arundell, Lady Baltimore, a member of the ancient family of Arundells in Cornwall, England, and the wife of Cecilius Calvert, 2nd Baron Baltimore (1605–1675), founder and first lord proprietor of the colony Province of Maryland.

Annapolis is the capital of the state of Maryland. It is the county seat of Anne Arundel County and its only incorporated city. Situated on the Chesapeake Bay at the mouth of the Severn River, 25 miles (40 km) south of Baltimore and about 30 miles (50 km) east of Washington, D.C., Annapolis forms part of the Baltimore–Washington metropolitan area. The 2020 census recorded its population as 40,812, an increase of 6.3% since 2010.