This treaty reduced the 2 million acre reserve to 256,000 acres including present-day Council Grove, Kansas, which became an important hub on the Santa Fe Trail. Notably, while the U.S. government recognized this land as belonging to the Kanza, U.S.

U.S. Congress passed this legislation, which facilitated the expulsion of Indigenous nations east of the Mississippi River into land west of the river. However, this “removal” constituted an invasion of eastern Indigenous people into Kanza homelands. During this era, the modern states of Nebraska, Kansas, and Oklahoma were designated “Indian Territory” and many Indigenous nations were confined to reservations in this region.  

The fact that the Kanza people’s first treaty of land cession with the U.S. followed the opening of the Santa Fe trail by four years was no coincidence. As non-Native people moved to and through this region from the Eastern U.S., more became interested in settling on the rich grasslands of the Kanza homelands. The Treaty of 1825 diminished the Kanza’s 20 million acre territory to a 2 million acre, thirty–mile-wide reservation, opening 18 million acres for speculation and settlement by certain U.S. citizens.

Missouri obtained statehood and the Santa Fe Trail opened. From 1821 to 1880, the Santa Fe Trail was a major trading route that extended from Missouri to Santa Fe, New Mexico. U.S.

This expedition marked the beginning of U.S. colonial incursions into the West. While the Spanish had settlements in the areas that would come to be known as New Mexico and California since 1598 and 1769 respectively, the U.S. government-funded exploration of the West by the Lewis and Clark expedition set the stage for land speculation and non-Native settlement in the Great Plains. Clark would go on to become general of the militia and superintendent of Indian affairs in St. Louis, negotiating land cession treaties in the areas he formerly explored.

The U.S. bought from France the Right of Discovery to Kanza and other Indigenous nations lands in the center of the continent. This was done without the knowledge or consent of these Indigenous peoples. The sale gave the U.S. the exclusive right to purchase these lands from Indigenous nations under the Doctrine of Discovery.  

This war leads to the establishment of an independent U.S. government. The new U.S. government adopted European approaches to colonialism, including the Doctrine of Discovery, which, by the 1830s, became the legal backbone for continued colonization, known as “Manifest Destiny.” This was affirmed in U.S. case law in a series of three Supreme Court cases that would come to be known as the Marshall Trilogy: Johnson v M’Intosh (1823), Cherokee Nation v Georgia (1831), and Worcester v Georgia (1831).

Père Jacques Marquette travels down the Mississippi River, mapping the land and people of the region for France. While Marquette did not interact with the Kanza, this map is evidence that Europeans were aware of the Kanza nation. From a legal perspective, maps like these were also sometimes used to establish “Right of Discovery” for the French, which Europeans used to rationalize colonization and seizure of lands occupied by sovereign nations.

The Kanza peoples are of the larger language and cultural group of the Dhegian-Siouan peoples (also including the Osage, Ponca, Omaha, and Quapaw). Kanza homelands are west of the Mississippi including the Tallgrass Prairie and Great Plains region.