Invincible's from Baltimore
I think this is the most explicitly an actual comic ever says "Invincible operates in Baltimore."
You can draw that conclusion from various character sheets/profiles, the scene in Brit where Donald's son goes to Mark's school and the school is stated to be in Baltimore, Mark's regularly wearing, like Orioles and Ravens gear in the comics, but I think Noble Causes #37 is the first time a comic ever says explicitly "Invincible is a superhero from Baltimore who protects Baltimore."
EDIT: Crown Pointe, where the Nobles live, is in Virginia, so it's not even that much of a flight for him.












