Navigating by map and compass is fast becoming a lost art. Understanding magnetic declination and the necessary compass adjustments is an integral part of outdoors navigation and orienteering.
Magnetic North vs. True North
Unfortunately the magnetic needle on your compass will only point to “magnetic north” which is generally very close to north, but far enough off to cause you navigation headaches. Declination refers to the angle which measures the difference between the direction your compass needle is pointing (magnetic north) and true north. This varies greatly depending on where you are in the world, and can even change over time! Best practice is to keep your maps updated. The diagram below shows you just how different these angles can be across the contiguous United States.
Compass Adjustment for True North
A simple compass adjustment will make sure you are able to find true north. Simply find the declination diagram on your map, typically printed at the bottom. Adjust your compass’ azimuth ring (or otherwise mark with tape/pen) as shown above. The goal is to make sure that while your compass needle is pointing towards magnetic north, your compass will still show you the direction of true north. Make sure to repeat this process for every trip, since declination is different all across the world.