Watervliet is a city in Albany County in the US state of New York. Watervliet is north of Albany, the capital of the state, and is bordered on the north, west, and south by the town of Colonie. The city is also known as "the Arsenal City".Watervliet is on the West Bank of the Hudson River. It is bordered on three sides by the town of Colonie; to the north by the hamlet of Maplewood, on the west by Latham and the hamlet of Mannsville, and on the south by the hamlet of Schuyler Heights. To the northeast is the town and village of Green Island. The Hudson River to the east is the boundary between Albany County and Rensselaer County, in Rensselaer County it is the city of Troy that borders Watervliet. The city is mostly flat but begins an extreme slope in the center of its most westerly edge, especially between the Watervliet Arsenal and 19th Street, an area once called "Temperance Hill".