In 1998 the Access Fund partnered with the Conservation Fund, Idaho Department of Parks and Recreation, and the National Park Service in the acquisition of a 1240 acre privately owned parcel adjacent to City of Rocks National Reserve for the purpose of subsequent transfer to the National Park Service and the eventual creation of a new park. The Access Fund provided crucial bridge funding to enable the purchase from the private land owner.

The AF also provided Congressional testimony in support of the acquisition, lobbied Senator Craig’s office to champion the purchase, and helped negotiate the land exchange between the state of Idaho and the NPS that allowed the acquisition to succeed. Ultimately the property was transferred to Idaho Parks & Recreation for designation as Castle Rocks State Park. This spectacular area contains more than 400 acres of towering granitic rock formations, rivaling the nearby City of Rocks as one of Idaho’s most important recreational rock climbing destinations. The area's geologic importance is confirmed by its listing on the National Registry of Natural Landmarks. Protection Method: partnership with the Conservation Fund, IDP&R and NPS.