Nelsonville is a Hudson Highlands village located in the town of Philipstown in Putnam County, New York, United States. The population was 628 at the time of the 2010 census. Nelsonville is directly east of the village of Cold Spring. On Main Street, the border is roughly demarcated by the western property line of the Baptist Church at the height of land, and by the property line along the rear of the church lot, extending south toward the Cold Spring Cemetery.