萊莉生於2247年，是一位生長在華盛頓特區遺址的一位孤兒，一直到有位不知名的軍人把她帶走並且教導她戰鬥和生存的本領，當這名軍人逝世時她才12歲；她就帶著他的遺體到阿靈頓公墓進行安葬。就在2273年也就是她26歲的時候，成立了萊莉遊騎兵團並進行首都廢土的繪地圖工作。Currently, she has suffered severe wounds and is in a coma in the ghoul stronghold of Underworld.
Before she meets the Lone Wanderer, her team was held up near Vernon Square by a large pack of super mutants where she was injured and nearly killed when she attempted to escape. Reilly keeps notes of her teammates in her terminal which are written as reports. According to her computer files, she and Butcher are in a complicated relationship, which she worries may jeopardize their professional relationship. In her terminal log about Donovan, she mentions having a contact in the Brotherhood of Steel.
- Reilly's Rangers: 在她甦醒後，她會敦促獨行者調查她小隊的下落，在弗農廣場的某處。
- Geomapping with Reilly: 在從國賓館救出她的小隊後，她會邀請獨行者做繪製特區地圖的工作並給予一個繪圖儀 。
- Depending on how she is woken up, Reilly's legs are crippled and can be seen limping if the Medicine skill is used to wake her up. However, she will look like normal if Doctor Barrows' Speech check is used to wake her up.
- If asked why there are so many mutants in the area she states that Brick thinks that there is something in the area they're looking for. As later discovered, they are searching for human abductees to expose to the F.E.V., which they use to make more super mutants.
- If one has the Gun Nut perk, a Speech option is available to say that the Lone Wanderer has heard of Reilly's Rangers before, and that they pack serious firepower. This has no other effect but variance.
* Only when she is in Underworld.
- There are a few inconsistencies between Reilly's dialogue and her notes. If asked about Talon Company, Reilly will tell about an encounter with them in which Brick, the team's Heavy Weapons specialist, almost fought with a detachment of them; where as in her report on Brick, Reilly states that Brick did indeed fire on (and nearly massacre) them. She also states that Theo, the ranger lost in the Statesman Hotel, was a full ranger, whereas his contract is marked in her notes as "probationary".
- Do not anger Reilly at all on the occasion where the quest is given. If the Lone Wanderer does, then goes and starts the quest another way, she and her rangers will become hostile. However, the Underworld residents will not become hostile to the Lone Wanderer and will attack Reilly. This also works the other way around, as if you attack Underworld residents, Reilly will help you in battle.
Reilly appears only in Fallout 3.
- Reilly's Rangers, choose to think about it and return later, but the quest already appears on your Pip-Boy and states "Find Reilly in Underworld". Carrying out a quick save before talking to her is recommended. 表达式错误：未预料的<操作符 Sometimes Reilly, when in Underworld's hospital, gets stuck in a dialogue with no exit options. This seems to occur when you listen to her quest suggestion
- If you have the Gauss rifle, and you remain hidden, in Underworld's hospital, then shoot Reilly while she is still unconscious, she will fall off the bed and stand up, but you wont be able to talk to her, though you are able to revive her with the required 60 Medicine. 表达式错误：未预料的<操作符