Ben Affleck as Sheriff Bryce Hammond

Peter O'Toole as Dr. Timothy Flyte

Rose McGowan as Lisa Pailey

Joanna Going as Jennifer Pailery, M.D.

Liev Schreiber as Deputy Stuart 'Stu' Wargle

Nicky Katt as Deputy Steve Shanning

Clifton Powell as Gen. Leland Copperfield

Rick Otto as Scientist Lockland

Valerie Chow Kar-Ling as Scientist Yamaguchi

Adam Nelson as Scientist Burke

John Hammil as Scientist Talbot

John Scott Clough as Scientist Shane

Michael DeLorenzo as Soldier Velazquez

William Hahn as Scientist Borman

Robert Himber as Scientist Walker

Bo Hopkins as Agent Hawthorne

Robert Knepper as Agent Wilson

Paul Schmidt as Church Soldier

Dean Hallo as Sgt. Harker

Clive Rosengren as Commanding Officer

Edmund Wyson as Cpl. Guthrie

Luke Eberl as Tunnel Boy

Judith Drake as Hilda

Yvette Nipar as Cowgirl

Lonny Chapman as Old Man at Bar (uncredited)

Linnea Quigley as Woman in Room 204 (uncredited)