Founded in 1722 by Jean St. Therese Langlois, the nephew of Fort de Chartres‘ Commandant Pierre Boisbriant, the village, as one history book recounted “never grew to any great size, and no event of importance seems to have marked its history.” Still, you probably want to know a few things about it.
The name (Rock Prairie) references the rocky bluffs next to the village. It was initially an agricultural village loosely associated with Fort de Chartres. Like most French colonial towns, Prairie du Rocher had a common field, three square miles of it, that the community shared for grazing. The village was home to 22 French-Canadian families in 1766, plus a few Illini Indians and enslaved blacks.
When Britain took control of the Illinois country, many of the town’s French residents moved across the Mississippi River to St. Louis or Sainte Genevieve. The town attracted a few new residents, though, so by 1800 about two hundred people called Prairie du Rocher home. Still, by 1840, the town had just one general store to go with its flour mill and saw mill.
The first Church of St. Joseph in Prairie du Rocher was built in 1734 and replaced in 1858. In 1881, it got a steeple and a new addition on the front. In the latter half of the 1800s, the church celebrated mass in French, German, and English.
Residents tried to incorporate in 1825 and 1835 but neither took. Prairie du Rocher finally became an incorporated village in 1871. Farming was the main occupation among its residents, but a few also worked in a nearby quarry.
Prairie du Rocher today still has a dozen buildings that date to the 1700s, like the Melliere House from 1735. A New Year’s Eve tradition known as La Guiannee also dates to the earliest times; to this day, some locals dress in 18th-century garb and go door-to-door singing the old French song of that name.
The village survived a close call with the Mississippi River in the Great Flood of 1993; the levee district’s late-night decision to blow an extra hole in the upstream levee might have made the difference.