How to pronounce Rensselaer | HowToPronounce.com www.howtopronounce.com/rensselaerPrivate View Rensselaer County, New York - Rensselaer County is a county in the U.S. state of New York. As of the 2010 census, the population was 159,429. Its county seat is Troy. Rensselaer, New York - Rensselaer is a city in Rensselaer County, New York, United States, and is located on the east side of the Hudson River directly opposite Albany.