Treaty of Fort Laramie (1851)
The Fort Laramie Treaty of 1851 was signed on September 17 between United States treaty commissioners and representatives of the Cheyenne, Sioux, Arapaho, Crow, Assiniboine, Mandan, Hidatsa, and Arikara nations. The treaty sets forth traditional territorial claims of the tribes as among themselves. The Native Americans guaranteed safe passage for settlers on the Oregon Trail in return for promises of an annuity in the amount of fifty thousand dollars for fifty years. The Native American nations also allowed roads and forts to be built in their territories.
Although many European and European-American migrants to western North America had previously passed through the Great Plains on the Oregon and Santa Fe Trails, the California gold rush greatly increased traffic. The United States government undertook negotiations with the Native American Plains tribes living between the Arkansas and Missouri Rivers to ensure protected right-of-way for the migrants.
Because the area around Fort Laramie lacked forage for the Indians' horses, the treaty was negotiated and signed 30 miles downriver from the fort at the mouth of Horse Creek. That is why many Indians referred to the treaty as the Horse Creek Treaty. Representatives from the Lakota, Cheyenne, Assiniboin, Gros Ventre, Mandan, Arikara, Hidatsa, Shoshone, Crow, and Arapaho took part in the treaty discussions. 
The United States Senate ratified the treaty, adding Article 5, to adjust compensation from fifty to ten years, if the tribes accepted the changes. Acceptance from all tribes, with the exception of the Crow, was procured. Several tribes never received the commodities promised as payments. The treaty produced a brief period of peace, but it was broken by the failure of the United States to prevent the mass emigration of settlers and miners during the Pike's Peak Gold Rush into the territories of the native nations as identified. The US government chose not to enforce the treaty to keep out the emigrants, although its economic wealth certainly allowed it to do so.
- Paragraph 69 REPORT TO THE PRESIDENT BY THE INDIAN PEACE COMMISSION, JANUARY 7, 1868
- Paragraph 33 Report to the President by the Indian Peace Commission, January 7, 1868
- Paragraph 35 REPORT TO THE PRESIDENT BY THE INDIAN PEACE COMMISSION, JANUARY 7, 1878
- "Treaty of Fort Laramie with Sioux, Etc., 1851." 11 StatsAffairs: Laws and Treaties — Vol. II: Treaties. Washington, D.C.: Government Printing Office, 1904, pp. 594–596. Through Oklahoma State University Library, Electronic Publishing Center.
- Map of North America following the 1851 Treaty of Fort Laramie at omniatlas.com