The summit of a dormant volcano nearly three miles high and located in the wilds of central Alaska—this is the unlikely site of a cosmic‐ray laboratory that was put into operation during the past summer. Established by an expedition under the joint sponsorship of New York University and the University of Alaska, and with the substantial assistance of the Army, Navy, and Air Force, the Mount Wrangell Observatory can now be added to the roster of the world's high altitude stations.