East Marion is a census-designated place (CDP) that roughly corresponds to the hamlet by the same name in the town of Southold in Suffolk County, New York, United States. The CDP population was 926 at the 2010 census.

The Town of Southold is one of ten towns in Suffolk County, New York, United States. It is located in the northeastern tip of the county, on the North Fork of Long Island. The population was 23,732 at the 2020 census. The town also contains a hamlet named Southold, which was settled in 1640.