Amsterdam is a city located in Montgomery County, New York, USA. As of the 2000 census, the city had a total population of 18,355. The name is derived from the city of Amsterdam in the Netherlands. The city of Amsterdam is surrounded on the north, east, and west sides by the town of Amsterdam and is on the banks of the Mohawk River. The majority of the city lies on the north bank, but the Port Jackson area on the south side is also part of the city.