Erin is a hamlet and census-designated place (CDP) in the town of town of Erin, Chemung County, United States. The population of the CDP was 483 at the 2010 census, out of a total town population of 1,962.
Erin is located in northeastern Chemung County, at the center of the town of Erin. It lies in the valley of Newtown Creek, a west- and then south-flowing tributary of the Chemung River, itself a tributary of the Susquehanna River. New York State Route 223 passes through the center of Erin, leading west to Breesport and to NY-13 near the village of Horseheads. Route 223 leads northeast to NY-224 in the valley of Cayuta Creek, which then leads farther east to Van Etten.
According to the United States Census Bureau, Erin has a total area of , of which is land and , or 1.26%, is water.
The school district is Horseheads Central School District.