1. St. Patrick's Day Celebrations: March 17 is a significant day for Montana's Irish community, as it is the day of St. Patrick's Day. From local parades to traditional music, dancing, and pub crawls, people in Montana often celebrate this holiday by embracing Irish culture.

2. The Creation of the Montana Territory: March 17 is also the anniversary of the creation of the Montana Territory in 1864. President Abraham Lincoln signed the bill that recognized Montana as an organized territory.

3. The Death of Jack Dempsey: On March 17, 1983, former heavyweight boxing champion Jack Dempsey died in New York City. Although born in Manassa, Colorado, Dempsey lived in Montana for a significant part of his life and is considered an important figure in Montana's sporting history.

4. Fort Missoula: St. Patrick's Day also marks the founding of Fort Missoula, which was established on this day in 1877. The military post served as a base for troops during the Indian Wars, World War I, and World War II.

5. Lewis and Clark's Journey: March 17 marks a significant event for Lewis and Clark's journey through Montana. On this day in 1805, the expedition reached the Great Falls of the Missouri River, a major landmark on their journey to the Pacific Coast.