Fenwick Island is a coastal resort town in Sussex County, Delaware, United States. According to 2020 census figures, the population of the town is 355, a 2.6% decrease over the last decade. It is part of the Salisbury, Maryland–Delaware Metropolitan Statistical Area. The town is located on Fenwick Island, a barrier spit.

Sussex County is located in the southern part of the U.S. state of Delaware, on the Delmarva Peninsula. As of the 2020 census, the population was 237,378, making it the state's second most populated county only behind New Castle and ahead of Kent. The county seat is Georgetown.