The town of Watervliet (/ˈwɔːtərvliːt/ WAW-tər-vleet) was a town that at its height encompassed most of present-day Albany County and most of the current town of Niskayuna in neighboring Schenectady County, in the state of New York, United States. Just prior to its dissolution, the town encompassed the current towns of Colonie and Green Island and the city of Watervliet.
On March 7, 1788, the state of New York divided the entire state into towns, eliminating districts as administrative units by passing New York Laws of 1788, Chapters 63 and 64. This transformed the Western District of the Manor of Rensselaerswyck into the town of Watervliet. In the census of 1790, the town had a population of 7,419, which made it twice as populous as the city of Albany.
The European settlement of Watervliet predated the creation of the town by almost 200 years. Fort Nassau on Castle Island was built by Dutch colonists in 1614 within the original boundaries of the town. It passed to the town of Bethlehem upon its creation in 1793, later to be annexed to the city of Albany in the 20th century. Early settlers were Dutch farmers owning land north and south of Fort Orange along the Hudson River. The lands to the north came to be known as Watervliet, while the lands to the south were named Bethlehem.