Sea Cliff, NY has a population of 5,069 and is the 6,410th largest city in the United States. The population density is 4,547 per sq mi which is 1167% higher than the New York average and 4919% higher than the national average. The median age in Sea Cliff is 48 which is approximately 25% higher than the New York average of 38. In Sea Cliff, 64% of the population over 15 years of age are married, 81% speak English and 7% speak Spanish. 77% of Sea Cliff residents were born in New York, 11% were born out of state, 1% were born outside of the United States and 11% were foreign born.