1. On July 23, 1806, the Lewis and Clark Expedition arrived at the confluence of the Yellowstone and Bighorn Rivers in what is now southeastern Montana. They were the first known white explorers to visit the area.

2. In 1883, the town of Miles City, Montana was incorporated. Located in the eastern part of the state, it was an important stop on the Northern Pacific Railroad and became a center for cattle ranching.

3. On July 23, 1903, the Montana State Industrial School, a reform school for delinquent boys, opened in the town of Miles City. The school was later renamed the Pine Hills Youth Correctional Facility and is still in operation today.

4. In 1937, a massive forest fire broke out in the Bob Marshall Wilderness area of western Montana, burning over 300,000 acres of land. The fire was started by lightning and burned for several weeks before being brought under control.

5. On July 23, 1986, the first section of the Beartooth Highway opened to the public. The 68-mile stretch of road runs through the Beartooth Mountains in southwestern Montana and northern Wyoming, reaching an elevation of over 10,000 feet. The highway is known for its scenic views and is a popular tourist destination.