What is the X in X-mas?
city, seat (1866) of Missoula county, western Montana, U.S. It is situated on Clark Fork of the Columbia River, at the mouth of the Bitterroot River, near the Bitterroot Range in a broad valley (elevation 3,223 feet [982 metres]). The first white settler in the area was Father Pierre-Jean de Smet, who in 1841 founded St. Mary's Mission at nearby Stevensville. Missoula originated in the 1860s as a trading post on the Mullan Road, a wilderness trail between Fort Benton, Montana, and Walla Walla, Washington. It was formerly called Hellgate Village (like Hellgate Canyon, reportedly named for the carnage found there by French trappers); the etymology of its present name is uncertain, but it is thought to derive from a Salish Indian phrase meaning "cold water." Its development was stimulated after 1883, when it became a division point on the Northern Pacific Railway, and with the founding there of the University of Montana in 1893.