Subsequently to the treaty of 1804, the erection by the government of the United States, of Fort Madison on the Mississippi, above the Des Moines rapids, gave some dissatisfaction to the Sacs and Foxes. This was increased by the British agents and traders, who instigated them to resist the encroachments of the Americans, now beginning to press upon their hunting grounds. Of this interference on the part of the British, with the Indians, there can be no doubt. Governor Harrison in a letter to the secretary of war, dated Vincennes, July 15th, 1810, says, "a considerable number of the Sacs went some time since to see the British superintendent, and on the first instant, more passed Chicago, for the same destination." General Clark, under date of St. Louis, July 20th, 1810, says, in writing to the same department, "One hundred and fifty Sacs are on a visit to the British agent by invitation, and a smaller party on a visit to the island of St. Joseph, in lake Huron." John Johnson, Esq. the Indian agent, at Fort Wayne, under date of August 7th, 1810, says, to the secretary at war, "About one hundred Saukees have returned from the British agent, who supplied them liberally with every thing they stood in need of. The party received forty-seven rifles, and a number of fusils with plenty of powder and lead."

McKee, Dixon, and Girty were open and active agents in exciting the Indians to attack the American frontiers. They held frequent talks with them and supplied them liberally with goods and munitions of war. In 1811, there being a strong probability of a war with Great Britain, a deputation of the Sauks and Foxes, visited Washington city, to see the President, by whom they were told that in the event of a war taking place with England, their great father did not wish them to interfere on either side, but to remain neutral: He did not want their assistance but desired them to hunt and support their families and live in peace. Immediately after the war of 1812, the Sacs and Foxes, with whom, as with Indians generally, war is the great business of life, felt that they ought, as a matter of course, to take sides with one party or the other, and went to St. Louis, to offer their services to the United States agent, to fight against the British; but the offer was declined, on the ground that the government of the United States had resolved not to employ the Indians in that capacity. The machinations of the British, were successfully continued. The Sacs and Foxes divided upon the question of taking up arms against the United States. A part of them claimed the protection of the American government and received it; a part joined the British standard, Black Hawk among the number, and fought against the Americans until the peace of 1815. The number of warriors who joined the British is supposed to have been about two hundred, and they have ever since been known as the "British Band," at the head of which has been "General Black Hawk."

On the 14th September, 1815, William Clark, Ninian Edwards and Auguste Choteau, commissioners on behalf of the United States, concluded a treaty with the chiefs and warriors of the Fox tribe, by which all injuries and acts of hostility, committed by either party during the late war, were to be forgiven, and peace and friendship established between the two nations. The fourth article of the treaty contains a recognition of the former treaty in these words. "The said Fox tribe or nation do hereby, assent to, recognize, re-establish and confirm the treaty of St. Louis, which was concluded on the 3rd of November, 1804, to the full extent of their interest in the same, as well as all other contracts and agreements between the parties." This treaty was made at Portage des Sioux.

On the 13th of September, 1815, the same commissioners, at the same place, concluded a treaty of peace and friendship with the chiefs and warriors of that part of Sac nation of Indians residing on the Mississippi river. The first article recognizes the treaty of 1804 in the following words. "The undersigned chiefs and warriors for themselves and that portion of the Sacs which they represent, do hereby assent to the treaty between the United States of America and the united tribes of Sacs and Foxes, which was concluded at St. Louis on the third of November 1804; and they moreover promise to do all in their power to re-establish and enforce the same." There is a further provision that they will remain distinct and separate from the Sacs of Rock river, giving them no assistance whatever, until peace shall be established between them and the United States. The Sacs on Rock river were that part of the tribe which had been engaged in the late war, and who now declined making a treaty with the United States, and continued, although officially notified of the peace, to commit occasional depredations on the frontiers; and, it was not until the following spring that hostilities on their part actually ceased.

On the 13th of May, 1816, the same commissioners effected a treaty with the chiefs and warriors of the Sacs of Rock river, and the adjacent country. The first article of this treaty provides, that, "The Sacs of Rock river and the adjacent country, do hereby unconditionally assent to, recognize, re-establish and confirm the treaty between the United States of America and the united tribes of Sacs and Foxes, which was concluded at St. Louis on the 3d November 1804, as well as all other contracts and agreements, heretofore made between the Sac tribe and the United States." Under the 9th article of the treaty of Ghent, concluded 24th December 1814, between the United States and Great Britain, it was stipulated, that each party should put an end to Indian hostilities within their respective territory, and place the tribes on the same footing upon which they stood before the war. Under this provision, the second article of the treaty with the Sacs of Rock river, stipulated that they are placed upon the same footing which they occupied before the late war, upon the single condition of their restoring the property stolen by them, from the whites, subsequent to their notification that peace had been made between the United States and Great Britain.

Under the 9th article of the treaty of 1804, the United States agreed to establish a trading-house to supply the Sacs and Foxes with goods at a more reasonable rate than they had been accustomed to procure them. On the third of September 1822, Maj. Thomas Forsyth, the U.S. Indian agent, made a treaty at Fort Armstrong, with the chiefs, warriors and head men of the Sacs and Foxes, by which, in consideration of the sum of one thousand dollars, they forever released the United States from all obligation contained in said ninth article of the treaty of 1804.

On the fourth of August 1824, at Washington city, William Clark, Indian agent and sole commissioner of the United States, effected a treaty with the Sacs and Foxes through their chiefs and head men, by which, for the sum of one thousand dollars per annum for ten years, they ceded all their interest and title to any lands claimed by them in the state of Missouri, which are situated, lying and being between the Mississippi and Missouri rivers, and a line running from the Missouri at the entrance of Kansas river, north one hundred miles, to the north west corner of the state of Missouri, and from thence east to the Mississippi. By this treaty, these tribes acknowledged the land east and south of the lines above described, so far as the Indians claim the same, to belong to the United States, and that none of their tribes shall be permitted to settle or hunt upon any part of it, after the first day of January 1826, without permission from the Superintendent of Indian affairs.

Upon the 19th of August 1825, William Clark and Lewis Cass, Commissioners on behalf of the United States, concluded a treaty at Prairie du Chien, in the territory of Michigan, with the chiefs and warriors of the Sioux, Winnebagoes, Menominees, Chippewas, Ottawas, Pottawatamies, Sacs, Foxes and Ioways. The objects of this treaty were the restoration of peace among the Indian tribes, several of whom had been for some time waging war against each other; the settlement of boundary lines between these tribes respectively, and between them and the United States. The Commissioners succeeded in effecting a peace between the Sioux and Chippeways, and between the Sacs, Foxes and Ioways on the one part, and the Sioux on the other; and also in adjusting the boundary lines of the territory of each tribe to the satisfaction of all parties. Under this treaty nothing was asked by the United States nor was any thing granted to them: the character in which the government presented itself, being simply that of a pacificator.

The concourse of Indians assembled at this council was very great. About 3000 came to the council ground, clothed in their war dresses, and armed with bows, war-clubs and tomahawks. The Sacs and Foxes were the last to arrive, but were very imposing and warlike in their appearance when they reached the ground. They ascended the Mississippi, to Prairie du Chien, in a fleet of canoes, lashed together. They passed and repassed the town in a connected squadron, standing erect, in their canoes, in full dress, singing their war songs. Upon landing, they drew up in martial order, as if in warlike defiance of their bitter enemies, the Sioux, who were encamped near the shore, and who in turn shot back the fierce look of hostility upon their ancient foe. An eye witness describes this scene as one unique and singularly magnificent. The council was held under a spacious booth of green boughs, and lasted for several days. Keokuk was present on this occasion, as the head chief of the Sacs, and took an active part in the council; his course being marked by that moderation and sound policy, for which he is eminently distinguished.