1. On April 11, 1899, the town of Sheridan, Wyoming, was incorporated. It was named after Civil War General Philip Sheridan and became an important center for the coal, oil, and gas industries.

2. In 1918, on April 11, the U.S. Army established the Cheyenne Aviation Repair Depot, which later became known as the Wyoming Air National Guard Base. It played a crucial role in World War II, providing repair and maintenance support for military aircraft.

3. On April 11, 1947, the University of Wyoming played its first intercollegiate baseball game against the University of Colorado. The Cowboys won 15-2 and went on to have a successful season.

4. April 11, 1955, was a significant day for the conservation movement in Wyoming. Governor Milward Simpson signed the Wyoming Wilderness Act, which protected large areas of the state from development, including the Fitzpatrick Wilderness in the Shoshone National Forest.

5. In 1986, on April 11, a severe winter storm hit Wyoming, causing significant damage and disrupting transportation and emergency services. Over 2 feet of snow fell in some areas, and strong winds created dangerous conditions on highways and in rural areas. The storm served as a reminder of the harsh weather that can occur in the state, especially during the winter months.