Rensselaer is a city in Rensselaer County, New York, United States, and is located on the east side of the Hudson River directly opposite of Albany. As of the 2010 census, the city population was 9,392. Rensselaer is on the western border of Rensselaer County. The area now known as the City of Rensselaer was settled by the Dutch in the 17th century. The city has a rich industrial history stretching back to the 19th century, when it became a major railroad hub; it remains a railroad hub because it is the site of a busy Amtrak station. Rensselaer was one of the earliest locations of the dye industry in the United States, and was the first American location for the production of aspirin.
The natives of the area called it Petuquapoern and Juscum catick, and the Dutch claimed the land in 1609 based on Henry Hudson's exploration of the Hudson River. Later the area was called "De Laet's Burg" in honor of one of the directors of the Dutch West India Co. Settlement occurred at least as early as 1628. By 1642 there was a brewery and many farms, also a ferry was established by Hendrick Albertsen running from the mouth of Beaver Creek in Beverwyck (Albany) to the future Rensselaer.