Chris Claremont, Paul Smith
Ann Nocenti, Arthur Adams, Carl Potts
The Xavier Institute, Salem Center, Westchester County, New York State, (former) The Alley (beneath Manhattans surface), X-Factor Is sentient starship
X-Factor Investigations Headquarters, New York City, New York; formerly Detroit, Michigan; mobile; Xaviers School for Gifted Youngsters, Salem Center, Westchester County, New York; Mojoverse; Cootermans Creek, Australian Outback, Australia; Alcatraz I