1) On October 31, 1936, the last horse-drawn wagon delivering mail was retired in Montana. The advent of motorized transportation marked the end of an era and signaled a shift towards modernization in the state.

2) October 31, 1961, marks the date of the deadliest plane crash in Montana's history. All 21 passengers and crew members aboard the Continental Airlines Flight 11 died when the plane crashed into a mountain outside Broadus, Montana.

3) On October 31, 1864, an event known as the "Battle of the Little Bighorn" took place in Montana. The battle was fought between U.S. Army troops led by General George Custer and a combined force of Sioux and Cheyenne warriors. The Native American forces won a decisive victory, which has since become an important moment in the history of the American West.

4) October 31, 1911, was the day that the town of Hardin, Montana, was officially incorporated. Hardin is a small town in southeastern Montana that has a rich history and is known for its natural beauty and outdoor recreation opportunities.

5) The Lewis and Clark Expedition passed through what is now Montana on October 31, 1804. The expedition, led by Meriwether Lewis and William Clark, explored the western territories of the United States and helped to map and understand the geography and natural resources of the region.