📜 Fort Belle Fontaine was the first U.S. military installation west of the Mississippi River, established in 1805. It also served as a vital trading post and is now a St. Louis County park with ruins and trails. 🔍 Listed on the National Register of Historic Places as an archaeological site. #Why Go 🏰 Explore historical limestone ruins and the Grand Staircase. 🌳 Hike a three-mile multi-purpose trail along the Missouri River. 🦅 Discover the natural beauty and wildlife observed by Lewis and Clark. 📸 Explore significant archaeological site. #Why Avoid ⚠️ Entrance shared with an active youth detention center, requiring a checkpoint stop. ⏳ Original wooden fort structures are gone; current ruins are from a 1930s WPA project. 🚫 Metal detectors are not allowed on the property. #Cost 💰 Guided tours $5/person. #Hours 🕒 Daily, dawn to dusk; gates open by 8 a.m. #🅿️ Parking Visitors directed to parking areas after stopping at a guard house.