Castle Rock Fishing Access Site offers an 80-acre facility located 15 miles west of Absarokee on Highway 420, featuring a dirt boat ramp that provides access to the Stillwater River for both motorized and non-motorized boating.

The site includes primitive camping (7-day maximum stay), toilets, water, and handicap-accessible facilities with spectacular scenic views.

According to the Upper Stillwater River Assessment, the ramp is steep and in need of repair to better accommodate recreational use and high water impacts.