1851 Captain Howard Stansbury surveys for a railway route. Steamboat ‘El Paso' sails up the Platte River to Guernsey, first steamship on the Platte River in Wyoming.

1852 William Vaux, post chaplain, opened first school in Wyoming at Fort Laramie, assisted by his daughter Victoria.  Peak year for emigration on Oregon Trail.

1853  Fort Supply, first agricultural settlement, established by party of Mormons near Fort Bridger.

1854 Grattan Massacre occurs near Fort Laramie.

1855 General W. S. Harney leads military expedition against the Sioux.

1856  Mormon ‘hand-cart' exodus enters Wyoming en route to Utah.

1857 Colonel A. S. Johnston's expedition marches across Wyoming against Mormons. Mormons burn buildings at Fort Bridger and Fort Supply. Camp Scott is established as winter quarters for Johnston's army; Jim Bridger leases Fort Bridger to the government. Lieutenant G. K. Warren explores Wyoming from Fort Laramie to the western slope of the Black Hills: Colonel E. V. Sumner leads troops against the Cheyenne Indians.

1858-59 Russell, Majors, and Waddell transport more than 16,000,000 pounds of freight to Utah, passing through Wyoming on Oregon Trail.

1859 Central, Overland, California and Pike's Peak Express Company is established by Russell, Majors, and Waddell. Fort Bridger becomes a government military reservation.

1860  Pony Express riders cross Wyoming. Second school in Wyoming established at Fort Bridger by Judge William Carter and Miss Fannie Foot is the teacher.

1861 Creighton completes transcontinental telegraph line across Wyoming. Pony Express discontinued.

1862  March: Ben Holladay takes over equipment of Russell, Majors, and Waddell. Indians raid stage line and steal equipment. July: Government mail route is changed from central Wyoming-Oregon Trail, to Overland (Cherokee) Trail because of Indian raids. Fort Halleck (1862-1866) established on Overland Trail.

1863 Bozeman Trail, through Wyoming, established. A Mormon freights a cargo of soda to Salt Lake, the first known export of mineral from the territory. Troops under General P. E. Connor sent to Wyoming to suppress Indians. De Lacy prospecting expedition discovers Shoshone Lake. First newspaper in Wyoming, The Daily Telegraph, begins at Ft. Bridger.

1864 Indians wage war along Platte in Wyoming as a result of Sand Creek Massacre in Colorado.

1865 January 5: First proposal for temporary government for Territory of Wyoming is made by James M. Ashley, later governor of Montana Territory. Fort Reno (1865-1868) built. Battle of Platte Bridge, Lt. Caspar Collins killed. Platte Bridge station renamed Fort Caspar. Powder River Indian Expedition under General Patrick Connor. The “Bloody Year on the Plains.”

1866  Fort Phil Kearny (1866-1868) built along the Bozeman Trail. Fetterman Massacre occurs. Nelson Story drove first herd of cattle through Wyoming, north to Montana. Fort Sanders (1866-1882) is built on Laramie Plains.

1867 Laramie and Carter Counties are created by Dakota Legislature. Union Pacific builds into Wyoming. Fort D.A. Russell, Camp Carlin, and Fort Fetterman (1867-1882) established. Town of Cheyenne is founded. Wagon Box Fight takes place in the Big Horns. Fort D. A. Russell (now Francis E. Warren Air Force Base) is established. Carissa lode (gold) is discovered at South Pass.

1868  Peace Commission signs treaties with Sioux, Crow, and Arapaho at Fort Laramie; with Bannock and Eastern Shoshone at Fort Bridger. Shoshone Reservation established. July 25: Territory of Wyoming is created by Congress. Fort Fred Steele (1868-1886).  Albany and Carter Counties are organized. Episcopal church is first church built in Wyoming (in Cheyenne).

1869  April 15. J. A. Campbell inaugurated as first governor of Wyoming. Cheyenne designated as territorial capital. First territorial legislature convenes. Act granting suffrage to women is approved (the first in U.S.). Union Pacific Railway is completed across territory. Carter County is changed to Sweetwater County. Uinta County is organized. Camp Augur (later Camp Brown, then Fort Washakie) established.

1870 Population (U. S. Census), 9,118. First homestead entry is perfected in the territory. Women serve on grand and petit juries at Laramie. Mrs. Esther H. Morris, of South Pass City, is appointed first woman justice of the peace.  Louisa Swain, of Laramie, cast first equal suffrage vote. Washburn and Doane Expedition explores Yellowstone National Park region.  Fort Stambaugh (1870-1878).

1871 Legislature passes Militia Act;  three militia districts are created.

1872 “Yellowstone Wonderland” is established as world's first national park. State Penitentiary is built at Laramie; destroyed by fire soon after; partially rebuilt in 1873.

1873 Wyoming Stock Growers Association organizes.