1. Formation of the Wyoming Territory
On August 21, 1869, President Ulysses S. Grant signed a bill creating the Wyoming Territory, which included land that would later become the state of Wyoming. The territory was named after the Wyoming Valley in Pennsylvania.

2. Total Solar Eclipse
On August 21, 2017, Wyoming was one of the best places in the United States to view a total solar eclipse. Thousands of people traveled to the state to witness the rare event, which occurs when the moon completely blocks the sun's light.

3. Wyoming Women's Suffrage
On August 21, 1869, Wyoming became the first state or territory in the United States to grant women the right to vote. This was the result of a successful lobbying effort by territorial legislators and various women's rights advocates.

4. Yellowstone National Park
On August 21, 1872, President Grant signed a bill creating Yellowstone National Park, the first national park in the United States and the world. The park, which is primarily located in Wyoming, spans over 2.2 million acres and is known for its geothermal features and wildlife.

5. Cheyenne Frontier Days
August 21 marks the final day of Cheyenne Frontier Days, an annual rodeo and festival held in Cheyenne, Wyoming. The event has been held since 1897 and attracts thousands of visitors each year. It includes parades, concerts, carnival rides, and various competitions, such as bull riding and steer roping.