On July 13, 1914 a referendum was presented to voters of Wasatch County to partition the eastern part into a separate county. The referendum passed, so Utah Governor William Spry issued a proclamation to take effect on January 4, 1915. The county seat was decided by county vote on November 5, 1914 election. The new county was named for its county seat, which in turn was called for the Duchesne River which flows southward and then eastward through the central part of the county near the city. Its name is of uncertain origin, but the holding theory is that it was named by fur trappers in the 1820s in honor of Mother Rose Philippine Duchesne, founder of the School of the Sacred Heart near St. Louis, Missouri, although other theories as to the name exist. The county boundary with Uintah County was adjusted by legislative act on March 5, 1917; Duchesne County boundaries have remained in their current configuration since that date.