It was there before the country was. When Lewis and Clark came through, the city formally changed ownership between three countries (Spain, France and the US) in a single day. There are still small French-speaking pockets in the area (Prairie Du Rocher, St. Genevieve) and neat French and British colonial forts, homes and buildings around. Before that it was at one point the largest city north of Tenochtitlan as part of the Cahokia complex, which controlled a wide ranging trade and cultural exchange network. The inhabitants left so many burial and ceremonial mounds that St Louis was called Mound City by the locals until around 1900. By that point the moundites had destroyed every mound they knew about to provide landfill and flood control along the river. And before that, well I can show you rocks in the area with fossils of sea life that are older than the concept of god by a couple hundred million years. I actually have some awesome crinoids and a rare Archimedes Screw (squid shell) I dug out of the Prairie Du Long Creek bed.