Holding room

Holding rooms were secure government locations — at places such as CTU Los Angeles and the FBI Washington Field Office — where suspects were detained or interrogated. In CTU they were situated down the corridor from the Bullpen, and underneath the Director of Field Operations' Office.

At CTU Los Angeles, there were at least three Holding Rooms.

CTU

"11:00am-12:00pm" - Tony Almeida and Nina Myers were detained in holding rooms by Alberta Green.
"1:00pm-2:00pm" - Jack Bauer was detained by Alberta Green.

"4:00pm-5:00pm" - Reza Naiyeer and Bob Warner were detained by George Mason.
"12:00pm-1:00pm" - Nina Myers was kept in Holding after she was brought in to CTU.

"7:00pm-8:00pm" - Gael Ortega was discovered as a mole and interrogated by Ryan Chappelle in Holding. Soon after Tony Almeida arrived and explained that he was not a mole and was working with him and Jack as part of an undercover operation.
"9:00am-10:00am" - Jane Saunders was detained but soon released by Tony Almeida.
"12:00pm-1:00pm" - Tony Almeida was kept in Holding by Brad Hammond after he committed treason.

"7:00am-8:00am" - Tomas Sherek was detained by Erin Driscoll, but Jack Bauer shot him in the leg while inside holding.
"2:00pm-3:00pm" - Sarah Gavin was framed by a corporate spy, Marianne Taylor, for leaking data to Henry Powell. Director Erin Driscoll, with help from Scott Borman, took the bait and had Sarah tortured. Later, Sarah was exonerated by Edgar Stiles, and she demanded compensation for her ordeal from Michelle Dessler, but she was sent away.
"12:00am-1:00am" - Joe Prado was detained by Jack Bauer, and soon let out under the terms of Amnesty Global.
"4:00am-5:00am" - Richard Heller was detained again until he divulged information about his sexual encounter with Gary.

"11:00am-12:00pm" - Spenser Wolff was taken to Holding after being revealed as a mole.
"6:00pm-7:00pm" - Christopher Henderson was tortured extensively by Rick Burke with pharmaceuticals after his capture by Jack Bauer, but then was transferred to the medical clinic during the gas attack.
"7:00pm-8:00pm" - Lynn McGill and Harry Swinton stayed there when CTU was contaminated with the Sentox nerve gas.
"9:00pm-10:00pm" - Audrey Raines is interrogated by Jack Bauer after Collette Stenger implicated her. Collette was also in a different holding room, and when Jack proved that she had lied about Audrey, he forced her at gunpoint to tell her where Vladimir Bierko was.

"7:00pm-8:00pm" - Nadia Yassir was detained, and interrogated, by Mike Doyle.
"1:00am-2:00am" - Jack Bauer was detained by Nadia Yassir.

"10:00am-11:00am" - Tony Almeida was detained and interrogated by Jack Bauer, then Larry Moss.
"5:00pm-6:00pm" - Sean Hillinger was detained after it was discovered that he was a mole.
"9:00pm-10:00pm" - Renee Walker was detained after aiding Jack Bauer.