Geography and politics
In this skill you'll find two closely connected topics. The first is, fundamentally, the lore of the land, the second the lore of the people that live on it. This skill does not enable the character to know how politics looked or worked before the Great War, but things like: Where are Shady Sands and Vault-City? Why do they keep snarling at each other all the time? Why does this bother Broken Hills, but not New Reno?
Bonuses and handicaps can be based, roughly, on distance. A character from New Reno knows how the political power structure works in his gangster metropolis and where exactly the Cat's Paw is situated on Virgin Street – but won't be that acquainted with the situation in the Angel's Boneyard in the deep south of the NCR.
The starting value is: 20 + 2 * I