1. On December 9, 1884, the town of Miles City was incorporated. The town, located in eastern Montana, was founded as a trading and transportation hub along the Yellowstone River. Today, it is known for its western heritage and outdoor recreation opportunities.

2. In 1958, a C-47 airplane belonging to the Montana Air National Guard crashed near Great Falls on December 9. All 17 aboard were killed in the crash, which was attributed to bad weather and pilot error.

3. December 9, 1967, marked the dedication of Lost Trail Pass Ski Area in southwestern Montana. The ski resort is located on the Montana-Idaho border and offers skiing and snowboarding terrain for all levels.

4. On December 9, 1915, the Montana State Capitol building in Helena was destroyed by a fire. The state government temporarily relocated to the Civic Center until a new capitol building could be completed in 1919.

5. December 9, 2013, was a significant date for Montana's energy industry. On that day, the Montana Public Service Commission approved the sale of Montana-Dakota Utilities to MDU Resources Group, a North Dakota based energy company. The sale was intended to benefit MDU's customers and shareholders in Montana.