The Manor of Rensselaerswyck, Manor Rensselaerswyck, Van Rensselaer Manor, or just simply Rensselaerswyck, is the name of a colonial estate—specifically, a Dutch patroonship—owned by the van Rensselaer family that was located in what is now mainly the Capital District of New York in the United States.
The estate was originally deeded by the Dutch West India Company in 1630 to Kiliaen van Rensselaer, a Dutch merchant and the company's primary investor. Rensselaerswyck lay on both sides of the Hudson River near present-day Albany and included parts of the present New York counties of Albany, Columbia, Greene, and Rensselaer, and it extended as far east as Pownal, Vermont.
The patroonship lasted successfully for more than two centuries, dying with its last patroon, Stephen van Rensselaer III in 1839. At his death, van Rensselaer's land holdings made him the tenth richest American in history to date. The manor was split between Stephen III's sons, Stephen IV and William. Farmers began protesting the fuedal system and the antirent movement was eventually successful, causing Stephen IV and William to sell off most of their land, ending the patroonship in the 1840s.