Isaac Vanderbeck Fowler (August 20, 1818 – September 29, 1869) was thrice the Grand Sachem of the Tammany Society, better known as Tammany Hall, from 1848–1850, 1857–1858, and 1858–1859, the last term shared with William M. "Boss" Tweed. He was appointed Postmaster of New York City by President Franklin Pierce on April 1, 1853 and was also a delegate from New York to the 1860 Democratic National Convention.