East Greenbush is a census-designated place in Rensselaer County, New York, United States. The population was 6,266 at the 2020 census. East Greenbush is mostly within the southern part of the town of East Greenbush, but a small section of the community extends southward into the town of Schodack. U.S. Routes 9 and 20 pass through the community, and the western end of U.S. Route 4 begins immediately north of the community.