North Greenbush is a town in Rensselaer County, New York, United States. North Greenbush is located in the western part of the county. The population was 13,292 at the 2020 census.

The town has three main hamlets, Wynantskill in the northeastern corner, Defreestville in the southern portion of the town, and Snyder's Lake which occupies the majority of the town's eastern end. Each have strong identities and hinder efforts by the town to have a centralized identity. Defreestville was originally called Blooming Grove until approximately 1830, when it was changed due to confusion with another Blooming Grove, in Orange County. Snyders Lake was composed of summer residences and continues to lack a central business district.

During the 20th century, North Greenbush began to see more development due to an improved transportation infrastructure which led to increased suburban residential, office, and retail growth based on the automobile. In 1931, the road between Troy and East Greenbush was widened and the right-of-way was straightened as US Route 4. The older, narrower, winding residential parts of the road were bypassed and is today's Bloomingrove Drive. But as time progressed, opposition grew in response to concerns about potential impacts on traffic and the environment. The RPI Tech Park site, which by October 1999 was one of only nine sites still being marketed by the state, was terminated when the North Greenbush town council voted to terminate the review process. Another instance of local opposition to development occurred after the construction of I-90's Exit 8 when that location became well-primed for commercial development. Local developer Frank Nigro, with Nigro Company, proposed a high-end shopping center for the northeastern corner of the intersection of routes 4 and 43. This led to lawsuits and a failed push by residents of Defreestville to incorporate as a village in order to stop the development and a counter-move by the developer and certain landowners to attempt annexation to the neighboring city of Rensselaer, where the development would be better received.

The Defreest Homestead was listed on the National Register of Historic Places in 1977.

Geography

According to the United States Census Bureau, the town has a total area of , of which is land and (1.74%) is water. The western section of the town is steeply sloped and cut by various ravines; the clay bluffs rise between 100 and above the river with little to no flood plain. The central and eastern parts consist of more gently rolling hills and valleys. The Hudson River is the river of the town, though it is inaccessible to the public at this time;

|footnote=U.S. Decennial Census

As of the census

Communities and locations in North Greenbush

  • Defreestville – A hamlet in the southwestern part of the town at the junction of US 4 and NY 43. The community derives its name from the local DeFreest family. The Sharpe Homestead and Cemetery and John Evert Van Alen House are listed on the National Register of Historic Places.