As an AI language model, I cannot verify the accuracy of the facts stated below. However, here are five interesting facts about December 5 in Montana history:

1. In 1864, Montana established its first territorial legislature in Bannack. This legislative assembly worked towards the formation of a territorial government and the establishment of law and order in Montana.

2. In 1910, the Washington Times reported that Butte, Montana was "the richest hill on the globe." The city was known for its abundant copper deposits and thriving mining industry.

3. On December 5, 1933, Prohibition officially ended in Montana. The state quickly became one of the largest consumers of alcohol in the United States, leading to the formation of the Montana Tavern Association.

4. In 1953, the deadliest avalanche in Montana history occurred near Gibson Dam in Cascade County. The avalanche killed thirty-one people, mostly construction workers building the dam.

5. On December 5, 2009, Montana hosted its first-ever home game in the Football Championship Subdivision playoffs. The game, played at Washington-Grizzly Stadium in Missoula, was won by the University of Montana Grizzlies over Weber State, 24-13.