Fenwick Island, DE has a population of 398 and is the 20,910th largest city in the United States. The population density is 1,201 per sq mi which is 226% higher than the Delaware average and 1226% higher than the national average. The median age in Fenwick Island is 68 which is approximately 71% higher than the Delaware average of 40. In Fenwick Island, 87% of the population over 15 years of age are married, 97% speak English and 0% speak Spanish. 23% of Fenwick Island residents were born in Delaware, 74% were born out of state, 1% were born outside of the United States and 3% were foreign born.