Alaska
from: http://touchngo.com/lglcntr/akstats/Statutes/Title09/Chapter65/Section200.htm
AS 09.65.200. Tort Immunity For Personal Injuries or Death Occurring On Unimproved Land.
(a) An owner of unimproved land is not liable in tort, except for an act or omission that constitutes gross negligence or reckless or intentional misconduct, for damages for the injury to or death of a person who enters onto or remains on the unimproved portion of land if
(1) the injury or death resulted from a natural condition of the unimproved portion of the land or the person entered onto the land for recreation; and
(2) the person had no responsibility to compensate the owner for the person's use or occupancy of the land.
(b) This section does not enhance or diminish rights granted under former 43 U.S.C. 932 (R.S. 2477).
(c) In this section, "unimproved land" includes land that contains
(1) a trail;
(2) an abandoned aircraft landing area; or
(3) a road built to provide access for natural resource extraction, but which is no longer maintained or used.