1. Montana became the 41st state in the United States on August 18, 1889. It was admitted to the union as a result of the Montana Enabling Act, which authorized the territory to draft a state constitution and allowed for its eventual admission to the union.

2. On August 18, 1936, Montana experienced one of the most devastating wildfires in its history. The blaze, known as the Blackwater Fire, started in the Swan Valley and quickly spread throughout the surrounding forests. It ultimately burned more than 152,000 acres and killed 15 firefighters.

3. August 18, 1975, marked a major milestone in Montana's environmental history. On this day, the state's Department of Environmental Quality was established, tasked with managing and preserving Montana's natural resources.

4. The first meeting of the Montana Constitutional Convention took place on August 18, 1884, in the city of Butte. The convention was responsible for drafting Montana's first constitution, which was ultimately ratified by the territorial legislature and sent to Congress for approval.

5. On August 18, 1974, the Anaconda Company, one of Montana's largest mining companies, closed its Berkeley Pit copper mine near Butte. The closure signaled the end of an era for Montana's mining industry and had a significant impact on the local economy. Today, the Berkeley Pit is a superfund site due to the environmental damage caused by the mine's operations.