1. On September 17, 1887, the University of Montana was founded in Missoula. The school started as the Montana State University with just four faculty members and 40 students. Today, it has grown to become one of the largest universities in the state, with over 12,000 students.

2. In 1912, Butte, Montana, experienced one of the deadliest mining disasters in American history when a fire broke out in the Granite Mountain-Speculator mine, killing 168 miners. The fire burned for three days, and despite efforts to extinguish it, only a handful of miners were able to escape.

3. September 17, 1920, marks an important day in the history of the Montana suffrage movement. On this day, Montana became the eleventh state to ratify the 19th Amendment to the Constitution, granting women the right to vote.

4. In 1934, on September 17, the Anaconda Copper Company, then the largest copper producer in the world, took out a full-page ad in the Anaconda Standard newspaper to announce that it was cutting wages by 10%. This move led to a massive strike in Butte that lasted for months, with clashes between miners and the company's private police force.

5. September 17, 1990, was the day the Montana Department of Environmental Quality ordered a halt to all mining activity in the state's Flathead River Valley due to concerns about water quality. The decision came after test results showed elevated levels of heavy metals in the river, linked to mining upstream from the valley. The ban on mining activity remains in effect in the area today.