Base
Serval Industries, Virginia; formerly X-Factor Investigations Headquarters, Starjammer; Xavier Institute for Higher Learning, Salem Center, Westchester County, New York; Genosha; X-Factor HQ, Washington D.C., Maryland; Mutant Research Center, Muir Island;
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