Many eastern Dakota were angered by the refusal of traders to extend credit during a summer of starvation and hardship, and the failure of the United States Indian agents to deliver annuity payments as required by treaty.

[1][2] The initial attack on the Lower Sioux Agency by a faction of the eastern Dakota focused on the four trading stores, which they proceeded to raid for flour, pork, clothing, whiskey, guns, and ammunition.

[3] After the initial conflict at Acton Township, Minnesota on August 17, in which five white settlers were killed by four young Wahpeton Dakota hunters from Rice Creek village, tensions were running high.

[2] However, "traditionalist" leaders such as Cut Nose, the "head soldier" of the soldiers' lodge,[3] and Red Middle Voice, the head of the Rice Creek band,[1] grasped that the situation presented an opportunity to lead an uprising against the Americans, who had withheld annuity payments and provisions during a summer of starvation and hardship for many eastern Dakota.

[2] Although Little Crow initially hesitated, warning that it was futile to go to war against the Americans, he eventually agreed to lead an uprising, and ordered an attack on the nearby Lower Sioux Agency the following morning.

[1] On the morning of August 18, several traders happened to be away from the Lower Sioux Agency, including Nathan Myrick, Major William H. Forbes, and Captain Louis Robert, leaving others in charge of their stores.

[3][5] On the morning of August 18, a large party of soldiers surrounded the Lower Sioux Agency, a settlement including the quarters of the Indian agent, other government personnel, traders' stores, barns, and other buildings.

[1] Many of the Dakota soldiers proceeded to raid the trading stores for flour, pork, clothing, whiskey, guns, and ammunition.

[1] Although a granite marker on the north side of the river gives his name as "Charlie Martel",[1] various accounts have suggested that the name of the ferryman was Jacob Mauley or Hubert Millier.

[3] As the Dakota attackers started crossing the river in pursuit, Olivier Martell, the proprietor of the ferry, had mounted his horse headed for Fort Ridgely.

[7] The violence escalated as Dakota soldiers attacked isolated homesteads in Brown and Renville counties, killing an estimated 200 settlers and taking another 200 women, children, and part-Dakota civilians hostage.