1. In 1939, the first full-scale oil refinery in Wyoming was opened in Casper on September 21. The Standard Oil Company of Indiana built the facility to process crude oil from the Big Horn Basin.

2. On September 21, 1867, Cheyenne became the capital of the newly-formed Wyoming Territory. Prior to this, the territorial government had been located in South Pass City.

3. In 1904, the University of Wyoming welcomed its first students on September 21. The school had been established in Laramie two years earlier after the Wyoming Territorial Legislature passed a bill creating the institution.

4. The first woman to serve in Wyoming's House of Representatives was elected on September 21, 1910. Jennie II. Haynes of Lander was a member of the Republican Party and won her seat in the legislature during a special election.

5. On September 21, 2001, family and friends gathered in Casper to remember the victims of the September 11 terrorist attacks. The ceremony featured Wyoming Governor Jim Geringer and U.S. Senator Mike Enzi, as well as religious leaders from a variety of faiths.