1. On September 20, 1909, the University of Wyoming football team played their first game against the Wyoming School of Mines. The Cowboys won 20-0 in what would be the start of a long-standing rivalry.

2. On this day in 1916, Wyoming's first public library opened in Cheyenne. The library was a gift from philanthropist Andrew Carnegie and still stands today as the Laramie County Library.

3. In 1935, Wyoming attorney and politician Nellie Tayloe Ross became the first female governor in U.S. history when she was sworn in as the 14th governor of Wyoming on September 20.

4. The Cheyenne Frontier Days rodeo, one of the largest and most popular rodeos in the world, held its first event on September 20, 1897. Today, the event draws over 200,000 spectators every year.

5. On September 20, 1917, the United States Army established Camp Dyer near Douglas, Wyoming as a training base for troops in World War I. The camp was named after Colonel Edward Dyer, a distinguished veteran of the Indian Wars and Spanish-American War.