Cobb Island is a small island located at the confluence of the Potomac and Wicomico rivers in southern Charles County, Maryland, United States. It is located approximately 45 miles (72 km) south of Washington, and is considered to be within the Washington, D.C. MSA. Cobb Island is separated from the mainland by Neale Sound and connected to it by a 0.11-mile-long (180 m) fixed bridge carrying Maryland Route 254.