The roots of the Posey War ran deeply through the history of San Juan County. In the 1880s cattle companies, Mormon and Gentile settlers, and Navajo herders and hunters all began to place increasing demands on the natural resources traditionally claimed by the Weeminuche Utes and San Juan Band Paiutes. By the early 1900s, the hunting and gathering lifestyle of the Utes and Paiutes was totally impractical; therefore, as the natural food supply and grass diminished, the Indians went to the next best source to obtain sustenance--the settlers. Friction, threats, counterthreats, and depredations ensued, with violence breaking out in 1915 and 1921, at which times settlers killed or wounded small numbers of Utes and Paiutes.

By 1923, Posey, a Paiute who had married into the Ute band in Allen Canyon, had become the symbol of this mutual antagonism. Approximately sixty years old, Posey had been involved in the previous conflicts, acquiring a reputation for arrogance and thievery. He naturally came center focus when in March 1923 Sheriff William Oliver arrested two Utes, Joe Bishop's Little Boy and Sanup's Boy, for robbing a sheep camp, killing a calf, and burning a bridge.