The Green Room was a place located in Chicago, Illinois. The Beautiful Room, as it was sometimes called, was a room where the angels kept people they wanted to protect. The name was given by Dean Winchester when he asked Castiel about it. The real location of the room was an abandoned factory in California.
The room itself served the person inside with whatever food and drink they found most appealing. It also had pictures of angels and archangels on the walls. One painting that stood out is of Michael killing Lucifer. There were also very antique-looking pieces of furniture around the room — this gave it a very regal look.
The room also had one door that the angels could make disappear at will. In addition, the room could regenerate anything that became damaged. Once the room had served its purpose, it returned to being what it was; an empty, dusty office.
The first person in this room was Dean Winchester. This was also the room's first appearance, as it was seen when Dean is whisked away by Zachariah. In the room, it had Dean's favorite brand of beer and double bacon cheeseburgers from a place he liked. However, Dean did not touch anything in the room, being more occupied with trying to see Sam. It was here Zachariah revealed the angel's intention to let The Apocalypse start, so they could defeat Lucifer. He tried to leave, and Castiel made the door disappear. Eventually, Dean nearly partook in the food but Castiel agreed to help him escape and stop the death of Lilith, and after banishing Zachariah, Castiel teleported Dean from the room.
The second person in this room was Dean's half-brother, Adam Milligan. Zachariah brought Adam here, he noticed that the brothers had the same tastes before Zachariah revealed that he was lying to Adam, and that he was to be bait for Sam and Dean. Castiel brought Sam and Dean to the location (Dean was surprised the room wasn't in Heaven or Jupiter, or "a blade of grass. Not Van Nuys.") and cleared out all the angels by killing some and using an etching of an angel banishing sigil on his chest. Dean arrived to help Adam, but Zachariah appeared and overpowered Sam.
Zachariah tortured both Sam and Adam to coerce Dean who was horrified at seeing this. Very soon, Dean said "Yes" (to being possessed by Michael), and Zachariah called down Michael. After seeing his brother's disappointment, Dean killed Zachariah in the room using an Angel Blade. Whilst escaping, Adam was trapped with Michael. Afterwards, the room disappeared along with Zachariah's body and Adam. Adam was subsequently revealed to have been taken by Michael as his vessel.
- One of the paintings on the wall was "The Happy Accidents of the Swing", a French rococo painting featuring a young nobleman peeping under the dress of a lady on a swing and numerous stone angels.