Reilly's Rangers (quest)

 is a Fallout 3 quest. It is also an Xbox 360 and PC achievement.

Objectives and walkthrough
Reilly's Rangers is a map service group in the wastelands of Fallout 3. There are five members of Reilly's Rangers.

This Quest can be started in two ways:

Exploring behind the National Archives building near the Mall Northeast map marker, you will pick up a distress radio signal from Reilly's Rangers needing assistance. (Which evidently leads to the one below.)

You meet Reilly in Underworld, the Ghoul City situated in the Museum of History in DC (close to the Museum of Technology and the Washington Monument). Reilly was wounded on one of her excursions by Super mutants, and is laying unconscious in Underworlds hospital. If you manage to wake her up (high medicine skill), she will ask you to help her team of Rangers, who are trapped on a hotel roof not far away.

The quest rewards for this are either a suit of Ranger Body Armor and or Brick's special mini gun Eugene.

The Fission Battery required to repair the elevator can be found on the floor just bellow the roof. Follow the quest map indicator. Or you can just bring one.

After rescuing Reilly's Rangers and offering Reilly your help for their mapping service once you return to the ranger compound, she will give you a GeoMapper Module. As long as have the module in your inventory, it will record every new location you discover, for which Reilly will pay you in caps every time you return to the Ranger Compound and talk to her.

If you manage to get the Mapping Module early in the game, you will basically earn caps for every location you discover. It will also count for the locations you have already discovered before receiving it. Talk to Reilly again about it and she will pay you.