Even if it carries the name of the infamous Bourbon County, the whiskey called Bourbon can be legally made anywhere in the US. Even though most Bourbon is made in Kentucky, there is a list of states that distill bourbon outside of Kentucky, including Tennessee, Ohio, Pennsylvania, California, Washington, Virginia, Colorado, New York and the list keeps growing.
Bourbon is regulated, instead of by region, by what make up the grain mixture in the mash for fermenting. It must be AT LEAST 51% Corn, with the rest being comprised of any cereal grain. It can only be distilled to no higher that 160 proof. It must be aged in NEW American oak, that has been charred. The proof of the distillate going into age must be NO Higher than 125.5 proof.
— Forrest Cokely