1870 - President Grant established the Sioux Reservation in South Dakota.
1892 - Wyoming Governor Barber telegraphed President Benajamin Harrison for help in the Johnson County War. Harrison ordered the situation be addressed under Article IV, Section 4 Clause 2 of the U.S. Constitution. The 6th Cavalry arrived on April 13 and took the Wyoming Stock Growers Association (WSGA) into custody.
1934 - Harry Sinclair bought the town of Parco and renamed it Sinclair in December of 1942.
"Every woman of the age of eighteen years residing in this territory, may, at every election cast her vote; and her right to the elective franchise and to hold office under the election laws of the territory shall be the same of electors."