The Alderney State Correctional Facility is a prison in south Alderney in Grand Theft Auto IV. It overlooks the West River and Algonquin. The prison is designated in the game to be it's own area, not administrated by Acter Industrial Park which encloses it. It appears to be a medium security prison, as there are many armed guards guarding the area, barbed wire fences and guard towers. It is not a maximum or supermax security prison, as such facilities are not located in or near most major cities. Inmates can be seen idling around, sweeping the prison grounds, and watering the grass. A chapel is located in the southeastern section of the prison where a preacher is sometimes seen preaching there.
Niko Bellic will not receive a wanted level if he enters the prison unless he injures an inmate or guard. However, Johnny Klebitz and Luis Fernando Lopez will receive a three-star wanted level upon entering the facility, with the facility's alarm going off. Ways to gain access inside the prison include the use of a helicopter or a tall vehicle like the Yankee to climb over the wall. In multiplayer mode, the main gate to the prison is unlocked so the player can drive through the entrance into the grounds. There are no guards or inmates in multiplayer mode.
- The only known inmate currently serving time is Gerald McReary. He received a lengthy sentence for various charges including racketeering and armed robbery.
- Aiden O'Malley was supposed to be transferred there on charges of grand larceny but was rescued and executed in the mission Tunnel of Death.
- Billy Grey served time after he was arrested in the mission This Shit's Cursed, most likely for a parole violation, but was killed while inside during the mission Get Lost when The Lost Brotherhood broke into the prison.
- When viewed from far away, the large fenced-in concrete recreational area inside the prison appears as a baseball field. The most likely reason for this is that there might have been a baseball field there at some time during the game's development, but it was removed, with the developers forgetting to remove the low-resolution texture, similarly to how a second control tower can be seen at Fort Baxter Air Base when seen from a distance in Grand Theft Auto: Vice City.
- If Niko calls 911 in the facility, he would say that he does not know where he is. The only other time this happens is if one drives a boat far out to sea and dials 911.