Fort Kaskaskia State Historic Site is a 200-acre (0.8 km²) park near Chester, Illinois, on a bluff-top overlooking the Mississippi River. It commemorates the vanished frontier town of Old Kaskaskia and the support it gave to George Rogers Clark in the American Revolution.
In 1881, during a flood, the moving water of the Mississippi “discovered” a much smaller, parallel riverbed, the mouth of the Kaskaskia. Kaskaskia’s bed was a few feet lower than the Mississippi’s bed, so the whole river shifted to the new watercourse, cutting across the head of a former oxbow to do so.
For the village of Kaskaskia, the river’s new course was disastrous. Their village had been by the waterfront of the much smaller river; now the mighty Mississippi was swallowing the town up. Even the village cemeteries were at risk.
In an emergency operation, 3,000 graves of the departed of Kaskaskia were exhumed and the remains reburied atop the bluff to the east, at the site of old Fort Kaskaskia. The state of Illinois agreed to maintain the site forever as a memorial to the vanished historic village.