Direct access from Castle Creek Road to Costo Lake Trail is not possible due to private land. This trail must be accessed from Lowline Trail, 438, or Mill Castle Trail, 450. Users can gain access to these trails from Mill Castle Road, Forest Road 727, on Ohio Creek Road.
Costo Lake Trail is closed to motorized vehicles because of its location within wilderness boundaries. The trail begins at 9,670 feet as it leaves Mill Castle Trail. It traverses a small rise then descends into the North Castle Creek drainage. The trail leads through a bog area about one half mile from Costo Lake. It follows the creek for a short distance and then ascends gradually to the lake.
Directions from Mill Creek Road: Hike north on the Lowline Trail, 438 or the Mill Castle Trail, 450. Both trails lead several miles north before intersecting with the Costo Lake Trail. The Lowline Trail is a more direct route.