1. Juneteenth Celebration: June 19th marks the celebration of Juneteenth, also known as Freedom Day, in Colorado. This day commemorates the emancipation of enslaved African Americans in the United States. It is celebrated with parades, music, and cultural events.

2. Statehood: In 1876, on June 19th, Colorado was admitted as the 38th state in the United States. This date is recognized as Colorado Day and is celebrated annually to commemorate statehood.

3. Gold Rush: The first gold discovered in Colorado was on June 19th, 1858, by Georgia prospector Lewis Ralston. This discovery sparked the Colorado Gold Rush, bringing thousands of miners to the area.

4. Tornado Outbreak: On June 19th, 1965, a severe tornado outbreak occurred in Colorado, with more than 10 tornadoes touching down in Weld County. The tornadoes caused 18 fatalities and more than 250 injuries.

5. Mountain Biking: The first organized mountain bike race in the United States was held on June 19, 1976, in Crested Butte, Colorado. The event was called the "Klunker Classic" and featured riders racing down a mountain course on modified bikes. This event is now considered the birthplace of modern mountain biking.