1. On May 27, 1935, the Supreme Court of Montana ruled that the state's Blue Sky Law was constitutional. This law was aimed at preventing fraudulent investments and required companies to register their securities with the state.

2. In 1943, on May 27, the Great Falls Tribune reported that Montana was among the leading states in the production of war materials, including copper, lead, zinc, and silver. These resources were crucial in supporting the country's efforts in World War II.

3. On May 27, 1964, the Anaconda Company reached a settlement with the Environmental Defense Fund over pollution from the company's copper smelter in Deer Lodge. The settlement required Anaconda to reduce its emissions and pay damages to affected communities.

4. In 1980, on May 27, the Montana State Legislature passed a bill requiring schools to teach the state's constitution as part of the curriculum. This was seen as a way to increase civic literacy and promote a better understanding of the state's government.

5. May 27, 2016, marked the one-year anniversary of the devastating floods that hit parts of Montana, causing millions of dollars in damage and displacing thousands of people. The disaster prompted a massive relief effort across the state and highlighted the importance of emergency preparedness.