Although still an operational military type, it's certainly old enough to be considered historic...
A UH-1H Twin Huey operated at Fairchild Air Force Base in Washington just reached an almost unbelievable 18000 flight hours.
http://www.fairchild.af.mil/News/Articl ... ght-hours/The aircraft has spent most of its service life at the base supporting the USAF survival school which had a facility on base but also operates in the Selkirk Mountains north of the base, not far from the Canadian border.