Ben Affleck
Sheriff Bryce Hammond
Peter O'Toole
Dr. Timothy Flyte
Joanna Going
Jennifer Pailery, M.D.
Liev Schreiber
Deputy Stuart 'Stu' Wargle
Nicky Katt
Deputy Steve Shanning
Clifton Powell
Gen. Leland Copperfield
Rick Otto
Scientist Lockland
Valerie Chow Kar-Ling
Scientist Yamaguchi
Adam Nelson
Scientist Burke
John Hammil
Scientist Talbot
John Scott Clough
Scientist Shane
Michael DeLorenzo
Soldier Velazquez
William Hahn
Scientist Borman
Robert Himber
Scientist Walker
Bo Hopkins
Agent Hawthorne
Robert Knepper
Agent Wilson
Paul Schmidt
Church Soldier
Clive Rosengren
Commanding Officer
Lucas Elliot Eberl
Tunnel Boy
Lonny Chapman
Old Man at Bar (uncredited)
Linnea Quigley
Woman in Room 204 (uncredited)