[BenKenobi]

I’d imagine Florida would have the largest magnetic declination?

[epithermal]

Actually one of the areas with the least declination:

[Gondring]

Actually, as you go farther north and east, you'll have the greatest separation between true north and magnetic north. In the midwest US, both are in about the same direction, it's just that the magnetic pole is closer. Then, in the western US, the farther to the northwest you go, the greater the separation between the two.

In this figure, the red arrow is toward the magnetic pole and the black one is toward true north. Note how the difference between arrows is greater the farther north you go, as well as the farther east or west you are from the magnetic north pole:

That gives us a map like this:

Of course, in Canada, it gets really funky, since you can be in an area where the you can be north of the magnetic pole, but south of the true pole...such as if you were up above the star (magnetic pole) on this figure:

[BwanaNdege]

"I’d imagine Florida would have the largest magnetic declination?"

Actually, much of Florida is close to zero. The largest declinations are in the northern states, especially the far NW & NE.

Here is a neat website to find your magnetic declination.

"http://www.magnetic-declination.com/"