Old Olney underground

 is a place added to Fallout 3 with the DLC Broken Steel, accessed via a ladder in Old Olney Sewer.

As part of the quest Shock Value the Lone Wanderer passes this area to reach the Olney Powerworks. It is inhabited by ghouls Kidd and Wint and a lot of Deathclaws. The ghouls (along with several more now-deceased friends) tried to establish a colony here, but disturbed a Deathclaw nest. Kidd and Wint were the only survivors.

Appearances
appears only in the Fallout 3 DLC Broken Steel.

Notable Loot
A Mini Nuke is found underneath a Teddy Bear next to a cupboard full of children's toys. The room is located behind the Lone Wanderer after he/she meets the first Deathclaw on a ramp. When at the top of the ramp turn around to see a small gap in the wall to the right. After entering the room you will notice the broken door so the gap in the wall is the only way to access the Mini Nuke.

Nuka Cola Quantum can be found behind a ham radio which is behind an average locked cell door. The door is in between two columns surrounded by rubble that split the path to continue onwards. It is near the counters with a workbench on it. The area which it is in is more like a garage than the hospital that was the player passes through and is beyond the mine that blows up the rubble blocking the tunnel.

A Sniper Rifle can be found behind some arching pipes next to two explodable generators within a chain-link fenced off area with a workbench to the right of the rifle. There are a couple boxes of .308 ammo in front of it. Continue further from the area of Nuka Cola Quantum and you should come across the area. It is the barely north of the most southwest corner of the map.