Moriarty Senior came to the former United States from Ireland with his young son, and amassed his wealth using the nearby trade routes, which helped secure Megaton as a trading hub in the area. He died during a raider attack in 2241 and his son inherited his wealth, including the saloon.
- Moriarty senior's son, Colin Moriarty, has an Irish accent (albeit an exaggerated one). The most obvious way for him to have such an accent is that he grew up hearing it, i.e. from his father, who would have had to be surrounded by other Irishmen to pick up such an accent.
- Fallout 3 Official Game Guide Game of the Year Edition p.66: "Colin Moriarty
Moriarty, 50, has been here nearly his entire life. He claims that his grandfather helped found the original settlement a few years after the war. His father used the nearby trade routes to amass wealth, which is used to help secure Megaton. Colin inherited this wealth when his father was killed during a Raider attack when Colin was 14. Colin's first move was to build a fence around the town. Since then, the people have looked to Colin as a benefactor despite his running drinks, Chems, girls, and games out of his saloon. Simms turns a blind eye to Moriarty's activities, because he is acutely aware that the town needs Colin's support and resources."
(Fallout 3 Official Game Guide Game of the Year Edition Wasteland Census)