Rock Creek Caverns

Summary
The Rock Creek Caverns are located in the east/southeast portion of the Capital Wasteland. The Caverns are accessed through a sewer grate at the bottom of a radioactive-water filled crater that has exposed the sewer system, just to the west of the National Guard Depot. The sewer network is attached to a short segment of the Metro system, which then descends into a cavern system filled with Mirelurks, Mirelurk Hunters, and Mirelurk Kings. There is lots of water - a Radiation Suit or Advanced Radiation Suit will come in handy.

Associated Random Encounter
There is a random encounter where three adventurers are attacked by a Deathclaw. If you save them, one of them will give you the location to Rock Creek Caverns. Even if you just run from the (heavily injured) death claw instead of helping them you will get the map if the main adventurer is still alive to talk to.

Notable Loot
There are 2 weapons cache in the area the first being much smaller then the second). The first area is a "room" covered with an assortment of junk such as the hood of a car, a fire extinguisher, and various cans and bottles in the larger of the 2 underground areas (if you look at the map, it is the circular little area sticking out). In the midde of the first chamber will be an outcrop of scalable rocks which will lead up to a small weapons cache and a Nuka-Cola Quantum. The second and main cache is at the end of the cavern system, where there are a number of dead adventurers and wastelanders and an ammunition cache, with (among other things) a Laser Rifle, Laser Pistol, Power Fist and associated ammunition. The main profit from this cavern is most likely the valuable Mirelurk Meat (valued at 20 caps ea.) and Softshell Mirelurk Meat (valued at 30 caps ea.), which can often be found in the eggs sacks littering the floor of the tunnels.