The history of the base cause of the US Army's actions in the Wyoming and Montana areas has become a lot clearer to me with the publication of a great article in the Smithsonian Magazine's website. It clearly documents the duplicity of Pres. Grant in starting an unauthorized conflict with the Lakota over the ownership of the Blackhills area after substantial gold deposits were found. Here is the link;
History, Travel, Arts, Science, People, Places | Smithsonian
This article brought to my attention that the Lakota fought a legal battle over the illegal 'taking' of their reservation area called "The Blackhills" and were in fact awarded the sum of one billion dollars. The Tribe has refused to take the settlement, but would rather have the Blackhills returned to their ownership. .............
It's not just the Black Hills that was taken. Take a look at the Ft Laramie Treaty of 1868. It established all of what is now South Dakota west of them Missouri river along with a big chunk of what is now the south west corner of north Dakota as the Great Sioux Reservation (over 25 million acres in total).
It also included almost all of the western half of Nebraska and the north easter corner of Colorado as the Article 11 Hunting Grounds, and the north east corner of Wyoming and the south east corner of Montana as the Article 16 unceded Indian Territory. These were areas where the Sioux would be allowed to hunt until the buffalo were gone.
The treaty also provided for an Indian Agency, grist mill, and schools to be located on the Great Sioux Reservation. In addition it provided for land allotments to be made to individual Indians; and provide clothing, blankets, and rations of food to be distributed to all Dakota and Lakota members living within the bounds of the Great Sioux Reservation.
In exchange for this "smaller" Indian territory the US government was supposed to remove all the forts in the powder river basin and prevent any white settlement in these areas.
Red Cloud signed the treaty after the forts were removed along the Bozeman as an act of good faith by the government and the tribal chiefs who already resided in the Great Sioux Reservation also signed the treaty. However 3/4ths of the males in the various bands of the Sioux did not sign the treaty and failed to abide by the proposed provisions and continued to live in the unceded territory (where they could hunt but not live under the treaty provisions).
To be fair, it can be argued that the Sioux as whole never agreed to the treaty, and this prompted the government to build more forts and create more Indian Agencies as part of a larger effort to confine the Sioux to the designated Great Sioux Reservation.
In the early 1870s, the government allowed Northern Pacific Railroad survey crews into the Unceded lands in WY, and that prompted complaints - and attacks from natives. The government response was more forts and more troops to protect whites and railway survey crews.
The government also violated the agreement in 1874 with the Custer Expedition into the Black Hills, which the government admitted was illegal but justified on the basis of needing to assess the mineral wealth in the area.
It's often said but not true that the 1874 expedition was the first to discover gold in the area, as prospectors had already made that discovery, but the 1874 expedition made it big news and prompted a god rush with the result that by 1875 the Black Hills was flooded with miners after the government failed/refused to clear them out.
In 1875 the government tried to resolve the issue by buying the Black Hills from the Sioux, but that was universally rejected by the various bands of the Sioux. Since the Sioux refused to negotiate another treaty, rather then uphold the 1868 Fort Laramie Treaty the government instituted a policy that declared the unceded lands off-limits and sought to force all Dakota and Lakota living in the unceded areas between the Black Hills and Bighorn Mountains within the confines of the Great Sioux Reservation.
In December 1875, the government plan became official policy. The people living in winter camps in the unceded territory were ordered to report to their agencies by January 31, 1876, or they would be regarded as hostile and the army would drive them in.
Some of the bands living in the area, refused to vacate by 31 January, and others living on the standing Rock reservation were given permission to hunt in the powder river basin due to food shortages in the sever winter of 1875-76. However they too were declared hostile after 31 January.
The government waited for warmer weather to drive them back to the reservation and kicked things off in June 1876 - and that's what launched the campaign against the Indians encamped on the Little Big Horn.
In 1877, partly in retaliation for LBH, the government moved to annex the Black Hills from the Great Sioux Reservation under the 1876 Treaty created by the 1876 Act. Per the 1868 treaty any changes to the treaty had to be ratified with the signatures from 3/4 of the Sioux adult males. They got something like 48 signatures, which was a fair bit short of required number. Congress ratified the 1876 Act anyway in February 1877 and the Act and Treaty also removed the rights to hunt in the Article 11 and Article 16 lands.
This meant that the "Great Sioux Reservation" was now reduced to what is now western SD, excluding the western third that contained the Black Hills, and a small bit of what is now North Dakota.
At this point, statehood became an issue for the whites living in the Dakota Territory and it became evident that with with 43,000 square miles of Indian land closed to any settlement or development, statehood was not going to happen.
As a result, in 1888 and 1889, federal commissions were sent once more to various Sioux agencies in attempts to get Indian approval of the Sioux Bill which called for the break-up of the Great Sioux Reservation into a four smaller reservations (Pine Ridge, Rosebud, Cheyenne and Standing Rock) and six smaller land areas, forfeiture of nine million acres of land, allotment of lands to individual families, and opening of non-allotted land to homesteading.
The various bands of the Sioux were naturally not impressed or in favor of this, so the commission sent people to put a great deal of pressure on tribal measure to sign the new Treaty of 1889 and eventually they coerced just over half to sign it.
The Sioux Bill in conjunction with the Dawes Act of 1877 finally opened the area to white settlement, which lead to statehood for SD and ND in 1889. This however required the Indian land allotments (basically 160 to 320 acres per family) to be made and Sitting Bull, among others refused to cooperate and accept an allotment.
This led to an effort to arrest Sitting Bull by Indian Police from the Standing Rock Agency on December 15, 1889. The plan was to arrest him and take him to Ft. Yates. This didn't go as smoothly as planned and resulted in the death of Sitting Bull, eight others in his hand and six Indian agents. His band then scattered. This event along with a the fears caused by the "Ghost Dance" religious movement occurring in 1889-1890 led to the military campaign to round the Sioux back up and this resulted in the Wounded Knee Massacre in 1890.
The Indian allotments were not completed until 1906 and the reservations continued to be whittled away until the land allotments in the Dakotas were completed in 1915 and reorganization of the reservation system in the 1930s resulted in the current reservations with a mix of reservation and allotted indian and white owned lands in SD.
It's complicated stuff but it's all connected and created a continuous chain of events, events that were probably far worse for the Sioux in the long run as a result of their victory at Little Big Horn - a truly Pyrrhic victory.