Blue Hell is the name given in the player community to the area found underneath the landmass in all Grand Theft Auto games. The player is not supposed to enter Blue Hell, but several game glitches (including 'holes' in the world terrain) can result in the player ending up there. When the player enters Blue Hell, they will fall for a few seconds before respawning on the nearest "solid" landmass. The Grand Theft Auto: San Andreas Blue Hell is the easiest to access and explore with the use of the in-game Jetpack.
- In Staunton Island LCPD Station, one of the higher walls is not solid. The player can easily enter and fall into Blue Hell. After the fall, the player will land in front of the station's car park entrance.
- In Esplanade North, San Fierro, the player will see several docks jutting out into the San Fierro Bay with warehouses situated upon them. Next to one of these docks is a submarine called the "U.S.S. Numnutz". If the player swims directly down from the submarine to the bottom of the waterway next to the dock, they will notice a greyish color which does not match the color or texture of the surrounding rock. This area is actually a hole that the player can swim through to enter Blue Hell.
- If the player stands on top of a San Fierro tram and takes a picture with the camera while on the tram, CJ may fall into Blue Hell and after a few seconds land on the sidewalk.
- Also in San Fierro, there is a large clothing store in Doherty, opposite the tract of wasteland. The top portion of the wall (between the top floor and roof) is not solid, and can be accessed with a jetpack.
- In Mulholland, Los Santos, there is a newspaper shop with a non-solid areas in the roof which will lead to the interior of the building, and from there to Blue Hell itself.
- At Las Venturas Airport, one of the walls of the main building has a glitch wherein running at it enough will pop the player through into Blue Hell. The wall is located where the fence around the runway meets the building.
- Also in Las Venturas, there is an unmarked Pay 'n' Spray east of the casino in the Come-A-Lot district. The southwest corner of the Pay 'n' Spray is not solid; if the player enters that spot via jetpack and lets CJ sink into the hole for awhile, he will fall into Blue Hell, later automatically spawning on the sidewalk outside the Pay 'n' Spray.
- If the player, while leaving the Atrium hotel lobby, aims a gun and quickly walks backwards, they may make it through the door and into the hollow shell of the building, without being transported into the actual lobby as would normally occur in gameplay. Though the first few metres of floor are solid, after this the floor is simply texture, and can be fallen through.
- Inside the Lil' Probe'Inn, in the room with the map of San Andreas, if players turn their back on the map and keep jumping on the boxes at the other side of the room, they may reach Blue Hell, and find themselves on the top of the bar, able to see its interior. In this case, the player can get back to the "real world" by jumping from the top of the bar, which will place them inside it again.
- Outside the Ammu-Nation in Red County, enter the Jetpack cheat (or use your own) and walk in front of the entrance. The yellow marker will disappear. When this happens, lift up and you will fly into Blue Hell.
- The player can use Blue Hell to re-enter the Area-69 interior after the "Black Project" mission.
- In the Ganton Gym once inside use the jetpack cheat and fly into a part of the roof (about a couple of steps to the left when you enter).
- In the mission St. Mark's Bistro, when the player is at the Bistro in Liberty City, using the jetpack cheat or the "kangaroo" jumping cheat to jump over the walls will cause the player to fall through the surface of Liberty City, and skydive for 30 seconds, until he reaches an invisible ocean with a partial copy of Easter Basin and Doherty, San Fierro nearby.
- Sometimes, when the player utilises the Swing Glitch they may be thrown into Blue Hell for a few seconds and then back on the surface somewere near the swing.
- Part of the south side of the Rotterdam Tower (just beneath the first high ledge) is non-solid, and can be entered with a helicopter to access Blue Hell. From here, the player can enter interiors they could not enter before, go underwater, and explore some buldings. The player may accidentally re-enter the "real world", however, as some "real" interiors are not visible from Blue Hell (this is especially true of tunnels), and entering these will restore the player to the normal game world.
- Upon entering the Schottler Medical Centre, turn right, and then right again. You will be in a long hallway, with some windows and hospital privacy screen directly in front of you. Throw a grenade near the wall; this will shatter the windows and move the screens. You can now jump through the window and walk around in Blue Hell for a while, however, if you venture to far towards the street, you will re-materisalise. A video of this can be found here; http://www.youtube.com/watch?v=_ogSKeOmu6Y