1. Montana Becomes a State: On December 1, 1889, Montana became the 41st state of the United States of America. The state was officially granted statehood after an enabling act was signed by US President Benjamin Harrison.

2. Great Northern Railway Reaches Montana: On December 1, 1890, the Great Northern Railway reached Montana, connecting the state with the Midwest and the Pacific Northwest. The railway played a significant role in the development of Montana, bringing in settlers and businesses and boosting the state's economy.

3. Mining Disaster in Butte: On December 1, 1904, a massive explosion at the Speculator Mine in Butte, Montana, killed 14 miners. The disaster was one of the worst in Montana's history and highlighted the dangers of working in the state's mining industry.

4. Montana State Flag Adopted: On December 1, 1905, the Montana State flag was adopted by the state legislature. The flag features a blue background with the state seal in the center and the word "Montana" above it.

5. Glacier National Park Established: On December 1, 1910, Glacier National Park was established in Montana. The park spans over 1 million acres and is home to stunning mountain ranges, glaciers, and abundant wildlife. It is one of Montana's most popular tourist destinations.