Delaware City is a city in New Castle County, Delaware, United States. The population was 1,885 as of 2020. It is a small port town on the e…Delaware City is a city in New Castle County, Delaware, United States. The population was 1,885 as of 2020. It is a small port town on the eastern terminus of the Chesapeake and Delaware Canal and is the location of the Forts Ferry Crossing to Fort Delaware on Pea Patch Island.