Dennison Ferry Green River Access. Part of the Mammoth Cave National Park "Blue Water Trail". Dennison Ferry requires a fairly steep carry-down to the water. The park service provides wooden slides on the stairs for canoes and kayaks, but secure all gear beforehand or it may wind up floating downriver. NO FISHING LICENSE REQUIRED IN PARK LIMITS For More info see: http://fw.ky.gov/navigation.aspx?cid=1061&navpath=C117C854.