Built into the remnants of an ancient sea floor, this is Hills Mills Tunnel in Dickenson County. It’s 448′ long and was faced up in 1920. However, as you can see, the years haven’t been kind to the right side of the facing. Note the old power line draped over the portal. Most all these tunnels once had working lights in them, probably for work crews. We’re now 9.05 miles from Elkhorn City, moving south. Next up, Russell Tunnel.