Rensselaer Westerlo (May 6, 1776 – April 18, 1851) was a United States representative from New York and a member of the Livingston family.
He was the son of Catherine Livingston (1745–1810) and her second husband Eilardus Westerlo (1738–1790).
Catherine Livingston was the daughter of Philip Livingston (1716–1778), and widow of Stephen Van Rensselaer II, and the mother of Stephen Van Rensselaer.
[1] Westerlo was active in the militia, and served as an aide to Stephen Van Rensselaer and commander of a cavalry regiment in the War of 1812.
In 1818 he became commander of New York's 3rd Cavalry Brigade with the rank of Brigadier General.