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The Treaty of St. Mary’s, 1818

The Treaty of St. Mary’s, signed in 1818, is six separate treaties signed in September and October of that year. These separate treaties were signed with the Native Wyandot, Seneca, Shawnee, Ottawa, Wyandot, Potawatomi, Wea, Delaware, and Miami nations. They sold a large portion of land in the middle of the state to the U.S. government. This moved the northern and northwestern boundary of the new state of Indiana to the Wabash River. The assortment of Native nations received other land, lump sum payments, and annuity payments in exchange.

The Miami gave up most of their lands south of the Wabash River in exchange for the Great Miami Reserve. It encompassed roughly 875,000 acres of land in northern central Indiana, being located just north of the northernmost treaty line of the Treaty of St. Mary’s. The treaty would also play a large role in helping divide and isolate different Miami villages, as the Miami lands beyond the Great Miami Reserve included six village reservations a few square miles large. These smaller village reservations ensured the Miami living there would be isolated and dependent.

Dependence on U.S. support was a manipulative strategy used to entrap Native nations by making them more and more dependent on their annuity payments given in exchange for land. To nations like the Miami, these payments began to replace practices like trading and trapping as their main form of income. The merchants and traders who acted as middlemen between Native nations like the Miami and the U.S. government made it easier for nations to quickly, and often predatorily, exchange their yearly payments for fine goods and alcohol. This was a common practice when dealing with Native nations all over America, trapping them in a cycle of reliance which always ended with more and more lands sold at bargain prices to the U.S. government.

Images

Treaty text<br />
Treaty text
The text of the Treaty of St. Mary's, intact and legible in large part thanks to the Indiana State Library. The library found the lost yet intact treaty in 2014 and restored it to its current state. Source: Courtesy of the Indiana State Library
Treaty marker<br />
Treaty marker
A historic marker comemorating the Treaty of St. Mary's and the new state boundaries as a result of the land bought in the agreement. This marker is located west of Delphi Indiana along U.S. Route 421. Source: Courtesy of Wikimedia commons Creator: Huwmanbeing
Treaty lines<br />
Treaty lines
A map showing the dates and treaty lines of several treaties located in southern Indiana. Towards the top shows the Treaty of St. Mary's, the largest section encompassing much of central Indiana. Source: Courtesy of the Monroe County Timeline
Settlement map<br />
Settlement map
A map from around the 1810s showing Naitve and White settlements before the Treaty of St. Mary's in 1818. Source: Courtesy of the Atlas of Great Lakes Indian History
Indian Removals<br />
Indian Removals
Illustrated here is a color coded map of Indiana showing the names of treaties, the associated dates, as well as the lands those treaties were related to. Look in direct center of the map to see lands ceded in the Treaty of St. Mary's. Source:

Courtesy of Wikimedia Commons

Creator: ArnoldPlaton

Location

Map

Metadata

Alex Haehner, “The Treaty of St. Mary’s, 1818,” Discover Indiana, accessed October 22, 2026, https://discoverindianahistory.org.curatescape7.reclaim.hosting/items/show/677.