Compass basics: bearings, declination, and not getting lost
A compass is one of the few pieces of gear where the $30 version does everything the $100 version does, and where owning one without practicing is the same as not owning one. The needle will point north whether or not you know what to do with that information.
Buy a baseplate compass
Skip the button compass on your zipper pull and the lensatic military model for now. A baseplate compass has a clear plastic base with a ruler, a rotating bezel marked in degrees, and a needle in liquid. The Suunto A-10 runs about $20 and is all most people need. If you want a step up, the Suunto MC-2 or Silva Ranger add a sighting mirror and adjustable declination for around $50 to $80. Whatever you buy, make sure the bezel turns with firm resistance and the needle settles fast.
What a bearing is
A bearing is a direction expressed in degrees, 0 to 360, measured clockwise from north. North is 0 (or 360), east is 90, south is 180, west is 270. “The lake is at a bearing of 240” is a precise instruction. “The lake is sort of southwest” is a guess.
To follow a bearing: turn the bezel until 240 sits at the index line, then rotate your whole body until the red end of the needle sits inside the orienting arrow on the bezel. Old-timers call this “red in the shed.” The direction-of-travel arrow on the baseplate now points where you want to go. Pick a distinct object along that line (a snag, a boulder), walk to it, and repeat. Sighting on objects beats staring at the needle while you walk, which is a great way to find every hole on the trail.
Declination, the part everyone skips
The needle points at magnetic north, not true north, and your map is drawn to true north. The difference is declination, and it varies by location: around 13 degrees east in Seattle, close to zero along a line through the Great Lakes and Gulf Coast, and around 12 degrees west in Maine. Your map’s margin lists the local value, though on older maps it has drifted, so check the NOAA magnetic declination calculator for the current number.
Ignore declination in Maine and every bearing you take is off by 12 degrees. Walk one mile on that error and you are more than 1,100 feet from where you think you are. In thick timber that is the difference between hitting the trail junction and walking past it forever.
If your compass has adjustable declination, set it once with the tiny key and forget it. If not, you add or subtract manually, and the easiest way to keep the sign straight is to write the rule for your own region on the compass with a paint pen.
Map and compass together
To take a bearing from the map: lay the compass edge along the line from where you are to where you want to go, rotate the bezel until its orienting lines parallel the map’s north-south lines, and read the bearing at the index. Ignore the needle entirely for this step. Then stand up, put red in the shed, and walk.
Two more habits worth building. First, take a back bearing (your bearing plus or minus 180) when you leave a fixed point like your camp or your truck, and write it down. Second, use handrails: follow a creek, ridge, or road that runs roughly your direction rather than holding a pure bearing through junk terrain. The compass keeps you honest, the terrain does the work.
Keep a compass in your bug out bag and another in your everyday hiking kit. It weighs an ounce. Metal objects and phone speakers throw the needle, so hold it away from your body and your gear when it matters.
Your next step
Set your local declination, then run the triangle drill in a park: walk 100 paces at 0 degrees, 100 at 120, and 100 at 240. You should finish within a few steps of where you started. If you do not, figure out why before the woods grade the test for you.