Anne Arundel County is a county located in the U.S. state of Maryland. As of 2000, the population was 489,656. The estimated population for 2003 was 506,620. It was named for Anne Arundell, a member of the ancient family of Arundells in Cornwall, England and the wife of Cęcilius Calvert, 2nd Baron Baltimore. Its county seat is Annapolis, which is also the capital of the state. It is pronounced (emphasis on the second syllable), different from the pronunciation of Arundel in Sussex in England as (emphasis on the first syllable). Speakers of Baltimorese and its variants in the County pronounce it "Annie Runnel".

This county is a part of the Baltimore-Washington Metropolitan Area. The center of population of Maryland is located on the county line between Anne Arundel County and Howard County, in the unincorporated town of Jessup.