1903 The greatest loss of life in any mine disaster in Wyoming occurred at Hanna on June 30, 1903, when 169 miners died when coal gas ignited in Mine No. 1.
1868 Benton Post Office was established on June 29, 1868 in Carter County. Benton was another railroad tent town that sprang into being in the year 1868 as the Union Pacific Railroad was being built.
1934 The Taylor Grazing Act became law on June 28, 1934. It was intended to "stop injury to the public grazing lands [excluding Alaska] by preventing overgrazing and soil deterioration; to provide for their orderly use, improvement, and development; [and] to stabilize the livestock industry dependent upon the public range" http://www.blm.gov/wy/st/en/field_offices/Casper/range/taylor.1.html
1943 On June 28, 1943, a B-17 enroute from Pendleton, OR to Grand Island, NE crashed in the Big Horn Mountains with 10 crew members aboard. The wreckage was not located until 1945. In 1946, the mountain on which the plane crashed was named Bomber Mountain. Read more about it in "The Bomber Mountain Crash Story: A Wyoming Mystery" by Wyoming author, R. Scott Madsen.
1874 Last Chance Post Office in Albany County was established on June 25, 1874. Last Chance was the name of a gold mine near Laramie.
1810 The Pacific Fur Company was founded June 23, 1810, in New York City.
1874 The steel Bridge over the Platte River near Fort Laramie crossed the river east of Fort Laramie. It was the fourth structure to span the river and is Wyoming's oldest bridge. The bridge still exists. It was authorized by Congress June 23, 1874 for $15,000.00. King Bridge Co., Cleveland, Ohio shipped spans and girders to Cheyenne by rail and they were then taken to Fort Laramie by mule train. The soldiers at Fort Laramie quarried the necessary stone. One span of the bridge broke loose during construction and had to be raised from the river bottom. The Bridge was first used March 1, 1876 by General Crook on his way to Powder River.
1925 On June 23, 1925 a section of mountain collapsed and dammed the Gros Ventre River. The slide formed Lower Slide Lake; two years later the dam gave way, flooding the town of Kelly.
1949 On June 23, 1949, Jackson Peak was officially named for William Henry Jackson by the U.S. Board on Geographic Names. It was described as being "an appropriate name because of Mr. Jackson's influence, as an artist and photographer with the Hayden Surveys (1870-79), in the development of the scenic West. He was one of the first men to photograph the Wind River Mountains. " (American Trails Association)
1844 "Thus died the man who heads the list of western heroes, but before closing the story of Dr. Whitman, I must refer to a letter written by him on June 22, 1844, addressed to Hon. James M. Porter, Secretary of War. Dr. Whitman had, on his visit to Washington during the winter of 1843, been asked to make suggestions as to the necessary aid the government could give to those going to Oregon. In response to this, he suggested the establishing of posts along the route to protect mountain travelers, these posts to be supplied with provisions for sale. Among other places, he urged that a settlement be made on Horse Shoe Creek, in what is now Wyoming, also at Laramie's Fork, another on the North Platte west of this point, on the Sweetwater, and on Green River. In his letter he says that at these places there is good land for cultivation and irrigation. It may be said to the credit of the government that it did, in part, a few years later, carry out the plans of Dr. Whitman by the purchase of the trading posts known as Fort Laramie and Fort Bridger. " (The History of Wyoming from the Earliest Known Discoveries, Volume 1 By Charles Griffin Coutant)
1873 "Saturday, June 21.—Broke camp at 5.30 a. m., in the midst of a driving storm of cold rain, which soon turned into snow, and marched 10.6 miles to the stage-station at Pacific Springs. Here the storm turned into a severe gale of cold wind. Wood, grass, and water at this camp, which is on the northern border of the hot sage-brush plain over which we have been traveling. This vicinity is the "South Pass" of the early geographers, about which there has been so much fictitious writing and picture-making. As there are no mountains about it, and as the old road hardly crosses a hill of any magnitude, the misnomer is evident. The road, however, crosses at this point the divide between the Atlantic and the Pacific flowing waters, and this gave origin to the name." Captain William A. Jones on his reconnaissance of Northwestern Wyoming, 1873