New Purchase Boundary (Treaty of St. Mary's)
Benton County, Benton County, Indiana
Marker Inscription
New Purchase Boundary (Treaty of St. Mary's) In October 1818, Purchasing Commissioners Lewis Cass, Benjamin Parke and Governor Jonathan Jennings acquired Indian claims on the land shown on this marker. About one-third of modern Indiana was involved in this transaction.
Erected by Indiana Historical Bureau
The Story
In October 1818, commissioners Lewis Cass and Benjamin Parke, with Governor Jonathan Jennings, negotiated the Treaty of St. Mary's, extinguishing Native land claims across a vast swath of central Indiana. The cession—the 'New Purchase'—opened roughly a third of the modern state to survey and settlement. The boundary it drew reshaped the map of frontier Indiana almost overnight.
Why it matters
The New Purchase was a pivotal act of dispossession and expansion, transferring Indigenous homelands to the United States and clearing the way for the rapid settlement of the Old Northwest.
The story behind this marker
AI contextThe era
In 1818, Indiana was brand new — admitted to the Union only two years earlier — and most of it was still Native homeland, not yet open to survey or settlement by the young state's citizens. The lands of central Indiana, including the country where this marker stands, remained under Indigenous claim, home to peoples who had lived there for generations.
This was the era of the Early Republic, when the expanding United States pressed steadily westward and treated the acquisition of Native land as the engine of that growth. The federal government's method was the treaty — negotiations, often conducted under heavy pressure, that transferred vast territories from Indigenous nations to the United States.
Against that backdrop, in October 1818, commissioners gathered to negotiate one of the largest such transfers in Indiana's history. What they arranged would redraw the map of the state almost overnight.
People & events
The marker names the men who acted for the United States: Lewis Cass, Benjamin Parke, and Governor Jonathan Jennings, serving as purchasing commissioners. Through the Treaty of St. Mary's, they acquired Native land claims across an enormous stretch of the state's interior.
The scale is hard to overstate. The transaction involved about one-third of modern Indiana — a swath so large that settlers and officials would come to call it simply the "New Purchase." With the stroke of a treaty, land that had been Indigenous homeland was opened to survey, sale, and settlement.
Behind the tidy language of "acquired claims" lies a harder reality. Treaties like this one were the legal instruments of dispossession, and the peoples who ceded their claims here were giving up ground their communities had long inhabited. The New Purchase was a gain for the young state and a profound loss for those it displaced.
Its place in the American story
The New Purchase opened the way for the rapid settlement of central Indiana, and its consequences arrived quickly. Land that had been closed was soon surveyed and claimed; within a few years the state would locate its new capital, Indianapolis, in the heart of this very territory.
That pattern — treaty, cession, survey, settlement — repeated across the entire Old Northwest and, indeed, across the growing nation. This single 1818 agreement is one clear, well-documented instance of the larger process by which the United States expanded across the continent and Indigenous nations were pushed from their homelands.
To stand at a boundary of the New Purchase, then, is to stand at one of the seams where two histories meet: the story of American settlement and statehood on one side, and the story of Native dispossession on the other. Both are true, and the marker's quiet arithmetic — about a third of the state — carries the weight of both.
If you visit
This is open Indiana countryside, and the thing to bring here is your imagination, because what the marker commemorates is a line — an invisible boundary drawn on a treaty map in 1818. You won't see a wall or a river marking it, only the land itself, which changed hands with the signing of a document.
Take a moment to consider what that boundary meant. On one side of a negotiation, a third of a future state passed from Indigenous nations to the United States. The peace of a quiet field today sits atop one of the more consequential — and painful — transactions in the region's history.
If you're exploring rural Benton County or traveling through this part of Indiana, the marker rewards a reflective stop rather than a quick photo. It's a place to think about how the ordinary, settled landscape around you came to look the way it does, and about the people whose homeland it was before the New Purchase redrew the map.
Written by AI to add context, grounded in the marker’s inscription and the historical record. The inscription above is the original, unaltered text.
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Related people
- · Lewis Cass
- · Benjamin Parke
- · Jonathan Jennings
Related events
- · Treaty of St. Mary's (1818)
Themes & tags
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