Fort de Chartres is a historic fortification located in Illinois, built by the French in the 18th century. It served as a military outpost and a center for trade and diplomacy in the region. The fort was strategically positioned along the Mississippi River, allowing it to control access to the river and protect French interests in the area. The fort's construction began in 1753, and it was completed in 1756. Over the years, Fort de Chartres changed hands between the French, British, and eventually the Americans. Today, it is a state historic site, offering visitors a glimpse into colonial military life and the early history of the Midwest.