Lewes is an incorporated city on the Delaware Bay in eastern Sussex County, Delaware, United States. According to the 2020 census, its p…Lewes is an incorporated city on the Delaware Bay in eastern Sussex County, Delaware, United States. According to the 2020 census, its population was 3,303. Along with neighboring Rehoboth Beach, Lewes is one of the principal cities of Delaware's rapidly growing Cape Region. The city lies within the Salisbury, Maryland–Delaware Metropolitan Statistical Area. Lewes proudly claims to be "The First Town in The First State."