It is kinda confusing. The zero declination line sort of follows the Mississippi River

North America Declination Map

Magnetic north is not at the North Pole (as most of you know), but is in or near Northern Canada. Check the map out. So if you are in Oregon, your compass wants to point east of true north. If you are in Georgia, your compass wants to point west of true north. Some people call the east positive and the west negative. Given that Gershon gave a positive 8.5 degree dec., that would mean that true north is on the west side of magnetic north. Same as magnetic north being east of true north. So Gershon's compass IS oriented properly assuming all else is correct cause I can't read the numbers at all .

Now these declination lines are very generalized. As a obvious example, lets say a economically feasible iron ore deposit lies undiscovered and you are trying to set declination according to your map...well, this would be pointless if you are near or on top of the deposit. This is an extraordinary example of a local field variation which is measurable, mappable, and generally wreak havoc on your compass readings. As mentioned in another thread by Gershon, even terrane can have an effect on the local field lines.