Rensselaer /rɛnsəˈlɪər/ 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 2020 census, the city population was 9,210. 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, who called it t'Greyn Bos, which became Greenbush in English. The city has a rich industrial history stretching back to the 19th century, when it became a major railroad hub; In 2020, Albany-Rensselaer was the ninth busiest Amtrak station in the country and the second busiest in New York State. Rensselaer was one of the earliest locations of the dye industry in the United States, and was the first American location for the product