Cape St. Claire, a suburb of Annapolis, is a covenanted, unincorporated community as well as a census-designated place (CDP) in Anne Arundel County, Maryland, United States. While the community of Cape St. Claire lies entirely within the CDP and accounts for approximately 80% of the homes and residents, the CDP also includes the smaller communities of Atlantis, Walnut Ridge, Green Holly, and St. Claire Court.