What three Native American groups formed an alliance to resist takeover of their land?

There were many shifting alliances between Native Americans during Westward Expansion. During the the Great Sioux War of 1876-77, which is also known as the Black Hills War, three specific Native American tribes formed an alliance against the illegal incursion of non-Indian settlers and the US army. These three tribes are the Lakota Sioux, Cheyenne, and Arapaho. After being legally guaranteed the territory of Black Hills in the Treaty of Fort Laramie, the discovery of gold led to the intrusion of miners and settlers, whereby the army intervened, not to expel but rather to protect the non-indian settlers and relocate the allied tribes. Although the Arapaho and the Cheyenne had already formed an alliance by (around) 1811 to expand their territory, their alliance with the Sioux didn't foment until the 1820s in the context of intertribal warfare with the Crow Indians--who were seen as allies of the white man.