Meriwether Lewis and William Clark, in their famed expedition of the early 1800's, were the first Europeans to visit what now is Montana, in 1805. Two years later, Manuel Lisa established the first fur-trading post on the Big Horn River. That trading other posts were destroyed by hostile Indians. Montana's first permanent white settlement was made in 1841 by Father Pierre Jean de Smet, who founded Saint Mary's Mission.

Gold was discovered in the region in mid-century, which brought on a rush of settlers. Western Montana, which had been part of both Oregon and Washington territories, was united with eastern Montana in 1863. The eastern part had been, at various times, included in the territories of Louisiana, Missouri, Nebraska, Dakota, and Idaho. Further struggle and development ensued for the next 26 years before Montana was admitted to the Union as the 41st state on November 8, 1889.