Fort de Chartres State Historic Site is off SR 3, 11 mi. w. on SR 155. Once the seat of the French government in the Illinois country, the fort was the last French possession to be surrendered to the British, who held it 1765-72. The present structure is a restoration of stone buildings erected during the 1750s and 1760s. The site includes a museum, which features artifacts from the 18th-century French colony, and an interpretive center.