According to the Wyoming State Historical Society, on September 12, 1963, the king and queen of Afghanistan visited the University of Wyoming. On September 13, 1918, John Kenkel of Cheyenne was granted a patent for a pot lid holder that looked much like a pair of tongs. On September 14, 1950, President Harry Truman signed a law expanding Grand Teton National Park to its present size. On September 15, 1938, Black Kettle, an Oglala Sioux man who was killed by a sheriff's posse on Lightning Creek in 1903, was reburied in public ceremonies at the Wyoming State Fair. On September 16, 1988, Cincinnati Red Tom Browning pitched a perfect game against the Los Angeles Dodgers - he was from Casper.

According to the Wyoming Almanac, on September 12, 1973, winds of 100 mph were clocked in the Tetons and blew down 10,000 trees in a swath hundreds of yards wide and 15 miles long east of Jackson.

Also according to the Wyoming Almanac, when President Franklin D. Roosevelt traveled through southern Wyoming in September of 1935, he was presented with a gift of antelope steaks… three separate times.