To appoach Belle Island park at N37° 31.092 W077° 26.882 and use the footbridge to cross over the James River. There are also alternative ways to get over to the island, but this is the most interesting way to the cache.
Once over the bridge follow the trails past the historic sites and up the trail towards the Hydro Electric plant ruins.
The cache is located "inside" the ruins of Ole Belle Isle Iron Rolling, Milling and Slitting Manufactory. The only piece left is one wall from this 19th century factory. You will need to walk through the opening in the wall to get "Inside" the building.
Once on the opposite side of the wall from the trails look to find an opening in the wall near the ground. Cache is hidden behind a collection of bricks from the ground around the ruins please rehide the cache as well as you found it.