Dewey Beach is an incorporated coastal town in eastern Sussex County, Delaware, United States. According to the 2010 census, the population of the town is 341, an increase of 13.3% over the previous decade. It is part of the rapidly growing Cape Region and lies within the Salisbury, Maryland-Delaware Metropolitan Statistical Area. In 2011, the NRDC awarded Dewey Beach with a 5-Star rating in water quality. This award was given only to 12 other locations, one being neighboring Rehoboth Beach.