Natural Bridge State Park in south-central Wisconsin preserves the state’s largest natural arch and the Raddatz Rockshelter beneath it, both carved by weathering from ancient quartzite in the Driftless Area. Its wooded hills, prairie remnants, and cliff habitats support uncommon plants, including rare ferns and goldenrod. The site is also archaeologically significant: a 1957 excavation uncovered evidence of human use stretching back between 9000 and 8000 BCE, making it the oldest documented occupation site in the upper Midwest. A tourist attraction by 1870, the area later gained state park, natural area, and historic register protection while remaining intentionally undeveloped.