1. On August 11, 1877, a group of Nez Perce warriors under the leadership of Chief Joseph passed through the Bitterroot Valley in Montana during their flight from U.S. Army troops. The Nez Perce War was one of the last conflicts between Native American tribes and the United States government in the 19th century.

2. On August 11, 1919, a wildfire known as the Great Fire of 1919 broke out near Glacier National Park in Montana. The fire burned for several days and destroyed over 1 million acres of forest, as well as several small towns and homesteads. It remains one of the largest wildfires in Montana's history.

3. On August 11, 1934, the Union Bank & Trust Company in Helena, Montana was robbed by a group of five men. The robbers stole over $30,000 in cash and securities, but were later caught and arrested by law enforcement officials.

4. On August 11, 1961, the Montana State Fair opened in Great Falls, Montana. The fair featured a variety of attractions and events, including concerts, rodeos, agricultural exhibits, and carnival rides. It remains a popular annual event in Montana to this day.

5. On August 11, 2011, U.S. Senator Max Baucus of Montana announced that he would not seek re-election in 2014. Baucus had served in the Senate since 1978 and was known for his work on healthcare, tax reform, and trade policy. His retirement marked the end of an era in Montana politics.