Flynn Creek crater, about 8 kilometers south of Gainesboro in Tennessee, formed around 360 million years ago when an impact created a shallow depression about 3.8 kilometers wide and 150 meters deep. Rapid burial beneath shale later protected it, making it one of the better-preserved ancient impact craters known. The collision shattered and displaced surrounding limestone and dolomite, left a thick breccia lens, uplifted older rocks at the center, and folded and faulted the rim. Evidence indicates the impact struck a shallow marine setting. Later karst development produced caves, including Hawkins Impact Cave, and the site remains important for geology in Tennessee and for studying complex impact craters in layered sedimentary rock.