The main score of the movie, composed by Jerry Goldsmith, was named "September 11th 2001", because it was recorded on that day. Also, the movie's posters were changed after 9/11 because they showed an American flag flying upside-down; a new poster was put up featuring faces of the cast.
Winter and Yates are the names of two British chess champions.
Robert Redford had trouble with his saluting at first; it took about 20 takes for him to do it right in the early scene where his character is, ironically, teaching Aguilar how to salute.
When Irwin is punished by being forced to move a huge pile of rocks, Robert Redford was offered fake featherweight props, but he chose to carry actual rocks to make it more realistic.
During filming breaks James Gandolfini often played chess, which was a theme throughout the movie. Robert Redford read a dictionary or tossed around a baseball or football.
When Irwin tapes pictures of his grandchild on the wall of his cell, they are actually pictures of director Rod Lurie's son Hunter.
Mark Ruffalo did all of his own stunts during the helicopter battle scene.
Originally, Winter was supposed smoke cigars. James Gandolfini pleaded with Rod Lurie to drop the idea because he felt smoking cigars would remind audiences too much of Tony Soprano, his star-making role in "The Sopranos" (1999).
In the opening minutes of the movie, Gandolfini's character, Colonel Winters, remarks "My God, they should be naming a base after him!", referring to Redford's Gen. Eugene Irwin. In fact, the US Army already has a Fort Irwin, located in the Mojave Desert in California, although it is named for Major General George LeRoy Irwin.