The Parts of a Compass

Adjusting Declination is Important

By Molly Absolon for Backpacker

The difference between true north (how your map is oriented) and magnetic north (where your compass points) is called magnetic declination. In order to accurately trek to your destination along a bearing, you have to adjust and correct for it.

The line of zero declination, where true north and magnetic north intersect, runs from the southern tip of Florida to northern Lake Superior, and near that line, declination won’t much affect navigation. The further east or west you move away from the line of zero...