Southold, NY has a population of 6,261 and is the 5,595th largest city in the United States. The population density is 598 per sq mi which is 67% higher than the New York average and 560% higher than the national average. The median age in Southold is 53 which is approximately 40% higher than the New York average of 38. In Southold, 66% of the population over 15 years of age are married, 92% speak English and 1% speak Spanish. 75% of Southold residents were born in New York, 14% were born out of state, 2% were born outside of the United States and 9% were foreign born.