 In the Catskill Mountains, Pratt built the largest tannery in the world at its time, and built the town of Prattsville to accommodate the labor force necessary for the tannery, raising the town's population from around 500 to over 2000.Pratt was elected to the United States House of Representatives in 1836 and 1842.During his second term, in 1845 he first proposed the transcontinental railroad.