Rensselaer is a city in Rensselaer County, New York, United States, and is located on the Hudson River directly opposite Albany. As of the 2010 census, the city population was 9,392; in 1920, it was 10,832. The name is from Kiliaen van Rensselaer, the original landowner of the region in New Netherland. Rensselaer is on the west border of the county. Earliest settlement occurred as early as 1628. The city has a rich industrial history stretching back to the 19th century, when it became a major railroad hub, a distinction which it maintains as the location of the 14th busiest Amtrak station. It was one of the earliest locations of the dye industry in the United States, and 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 co-directors of the Rensselaerwyck Manor, which included the future city of Rensselaer. 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. Greenbush (originally Green Bosch in Dutch) was the earliest settlement from Dutch times, and a second hamlet East Albany, which was the area just north of Greenbush, was already a sizeable hamlet by 1815. The third hamlet that would be incorporated into the city was Bath (also Bath-on-Hudson), which was laid out in 1795 and settled even earlier, it was incorporated as a village in 1874.
The Van Rensselaer family, which were the feudal landholders of the entire future Rensselaer County built a residence in the future city of Rensselaer. This property was inherited by Hendrick van Rensselaer, Kiliaen van Rensselaer's grandson, who built Fort Crailo in approximately 1712. It was built on the site of where Dominie Megapolensis built his own house in 1642. Crailo was expanded in 1762-1768. At various times, the grounds were used as a campground for British and colonial troops. It is reportedly the place where, in 1755, British Army surgeon Richard Shuckburgh, quartered in the home, wrote the ditty "Yankee Doodle" to mock the colonial troops who fought with the British in the French and Indian Wars. Fort Crailo was declared a National Historic Landmark in 1961.