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Adjust a compass for declination
Magnetic north and true north are not the same. Declination is the correction that keeps you on the map.
Andrew Skurka — Adjust for Declination & Orient a Map
Step-by-step
Find the declination value for your area on your map's declination diagram or at magnetic-declination.com.
Determine whether the declination is east or west of true north.
On an adjustable compass, turn the declination screw until the orienting arrow matches the printed declination offset.
If your compass is not adjustable, add east declination to your magnetic bearing or subtract west declination.
Double-check by orienting the map: the compass needle should align with the map's north-south grid when the map is rotated correctly.
Tip: Declination changes slowly over years and sharply across regions. Always use a current value for the exact area you're in.
Related outdoor skills
Educational reference only. Wilderness conditions change fast — practice in low-stakes settings, take a certified wilderness first-aid course, and confirm regional regulations before you rely on any of these skills in the field.