Declination refers to magnetic declination – the difference between true north and magnetic north. This poses a conundrum when navigating and utilizing maps, as maps are oriented to true north, but your compass needle points to magnetic north. This difference between true north and magnetic north will be listed on any decent map and can be looked up online.

Magnetic declination will vary by location, and many compasses allow you to adjust for the exact declination of an area to make navigation easier.

Declination by Location and Declination Adjustment

Declination varies by location and changes over time. Most baseplate hiking compasses will feature a declination screw or adjustment mechanism, allowing you to quickly orient in the field. Digital compasses can be programmed with the declination (expressed in degrees) so that you’re shown true north in the field and not magnetic north.

More on Backcountry Navigation

For more on Navigation, see our complete navigation guide in the PDF version of Issue 56 of TrailGroove Magazine ($10 download or all included with an active Premium Subscription).

Editor’s Note: This Jargon installment originally appeared in Issue 55 of TrailGroove Magazine. You can read the original article here.