Johnston Atoll is #8 Most Wanted DXCC entity globally. It seems easy to ride a bike around there but difficult to operate ham radio where it’s commonly known DXpedition operators leave no footprints on such trips.
The Fish and Wildlife Service and the US Air Force are currently discussing future management options; in the interim Johnston Atoll and the three-mile Naval Defensive Sea around it remain under the jurisdiction and administrative control of the US Air Force.
Entry into Johnston Atoll is heavily restricted, and requires a special-use permit to visit, often from the U.S. Military or the US Fish and Wildlife Services. And they both generally only give permits to military personnel and civilian contractors. This even applies to U.S. and American Samoan citizens.