Rehoboth Beach is a city along the Delaware Beaches in eastern Sussex County, Delaware, United States. As of the 2010 United States Census, the population was 1,327, reflecting a decline of 161 (11.2%) from the 1,488 counted in the 2000 Census. Along with the neighboring coastal city of Lewes, Rehoboth Beach is one of the principal cities of Delaware's rapidly growing Cape Region.