Currently unrevealed, formerly Asteroid M; various hidden bases on Earth including one in Antarctica; an island in the Bermuda Triangle; Professor Xaviers School for Gifted Youngsters, Salem Center, Westchester County, New York
(current) Professor Charles Xaviers Institute for Higher Learning, Salem Center, Westchester County, New York (former) Muir Isle, Scotland,; a loft in Soho, Manhattan, Ust-Ordynski Collective, Lake Baikal, Siberia, U.S.S.R., X-Men Headquarters in Austra