AmenitiesJefferson County (Cedar Hill Park, 6801 Cedar Hill Rd): Big River access, picnic, restrooms. HAZARD: Cedar Hill Dam ruins immediately adjacent. ~RM 63.2. Coord = OSM slipway, corroborated by USGS 'Big River at Cedar Hill' (38.34990,-90.64444) and OSM Cedar Hill dam ruins (38.34992,-90.64405).