East Greenbush is a town in Rensselaer County, New York, USA. The population was 15,560 at the 2000 census. The word Greenbush is derived from the Dutch "Groenen Bosch," referring to the pine woods that originally covered the land. The first settlement of the land now known as East Greenbush was made by tenants under Patroon Kiliaen van Rensselaer around 1630. The town was formed in 1855 as the town of Clinton, the name changing to East Greenbush three years later. It is mostly suburban along its major highways and rural in the southwestern and northeastern corners. Interstate 90 passes through the town. It contains the west (or south) end of US Route 4 and the northern terminus of NY Route 9J; as well as US Route 9 and US Route 20. The last two are concurrent, under the name Columbia Turnpike, and is often referred to by locals as "9 and 20".