Thomas Fitzpatrick, c.1799–1854, American trapper, fur trader, and guide, one of the greatest of the mountain men, b. Co. Cavan, Ireland. He emigrated early to the United States, and by 1823 he was engaged in St. Louis for a trading expedition of William Henry Ashley up the Missouri. Like others of the mountain men, he spent many of the succeeding years opening up the West. He went with Jedediah S. Smith into the Green River country through the South Pass in 1824. Fitzpatrick worked for the Ashley interests until Ashley withdrew (1826) from the trade; then he was a trader for Smith, Jackson, and Sublette until 1830, when the Rocky Mountain Fur Company was formed with Fitzpatrick as senior partner. After that company was dissolved (1834), Fitzpatrick became a guide. He piloted the John Bidwell party, the first emigrant train bound for California, as far as Fort Hall in 1841, and the next year he performed the same service for the first train to Oregon. He gained some celebrity as guide to John C. Frémont on his second expedition and in 1846 was guide to Stephen W. Kearny on the march to Santa Fe. In Nov., 1846, he was appointed Indian agent for a large part of the present Colorado and was successful in negotiating treaties.
See L. R. Hafen and W. J. Ghent, Broken Hand: The Life Story of Thomas Fitzpatrick (1931); B. De Voto, Across the Wide Missouri (1948).