1803: The US buys the Louisiana territories, which includes much of Montana.

1805: Lewis and Clark explore much of Montana along the Missouri, Marias, and Yellowstone Rivers.

1863: The settlement of Bozeman is founded as a stop on the Bozeman Trail, an extension of he Oregon Trail.

1864: The Montana Territory is created from the Idaho Territory.

1864: The city of Helena (originally Crabtown) is founded after gold is discovered at Last Chance Creek.

1867: Fort Shaw is created west of the Great Falls of the Missouri River as a trading post and hospital. It was eventually used a school for Native Americans.

1875: Helena is named capital of the Montana Territory.

1876: U.S. soldiers from the 7th Cavalry are massacred at the Battle of Little Bighorn in eastern Montana by Lakota and Cheyenne warriors. 258 American soldiers are killed, including General George Custer in what came to be known as Custer's Last Stand.

1877: Cheyenne and Nez Perce Indians are driven from Montana by U.S. military forces.

1877: The settlement of Billings is founded as a stop on the Northern Pacific Railroad.

1882: The city of Great Falls is founded on the Missouri River. Originally called Johnstown, the site's geography was thought to have great potential for creating hydroelectric power.

1889: Montana becomes the 41st state.

1932: Montana's Glacier National Park and Canada's Waterton Lakes National Park become the world's first International Peace Park.