What Is True North? How to Find True North

True north, also known as geographic north or geodetic north, is the direction of the North Pole, the northernmost point of the Earth’s rotational axis. On a geological survey map, lines of longitude that span the globe from north to south mark the true north. The precise location of the Geographic North Pole is in the Arctic Ocean—unlike the South Pole, which is on Antarctica's landmass—and the shifting sea ice makes a fixed marker impractical.

The direction a compass needle points and the location of the North Pole differ. Consider the following differences between magnetic north and true north:

• Declination: The difference between magnetic north and true north, technically known as declination, depends on where you are on the Earth’s surface—or above it if you happen to be flying. Knowing the magnetic declination in your part of the world will allow you to calculate true north by how many degrees west or east of true north your compass is pointing. (Magnetic deviation, or the effect of nearby metallic objects, can skew your compass reading.)
• Fixed point: True north is a geographical fixed point. Magnetic north is where the needle of compass points towards the northern end of Earth’s magnetic field, so magnetic north does not perfectly align with true north. The magnetic North Pole shifts over time due to changes in the magnetic fields generated by the dense, slowly shifting metallic makeup of Earth’s core. The magnetic North Pole is currently moving westward at roughly 50 kilometers per year.
• Map projection: Grid north is the direction of north indicated on a map projection. The difference between grid north and true north is very slight and insignificant for most navigational tasks.

Depending on your positioning and what tools you have at your disposal, finding true north can take a little effort. Consider the following methods:

1. 1. Global positioning system: Many cell phones have GPS capabilities, and there are many dedicated navigation devices available to backcountry hikers and backpackers. GPS typically shows true north, removing any confusion or the need for extra calculations.
2. 2. Compass reading: Out in the wilderness, you can use a magnetic compass to calculate true north. For this to work, you’ll need to know the local declination value. You can find the declination value in the legend of a map of the area or online through various government agency websites, such as NGDC or NOAA. The declination number will be negative if you are east of the agonic line, positive if you are west. (The agonic line connects the north and south magnetic poles.) Using the bezel ring on your compass, adjust the orienting arrow until it points to the value of the local declination value. Then, turn the compass until the needle lines up with the arrow—the direction of the travel arrow on the compass will point to true north.
3. 3. Stars: The North Star, also known as Polaris, is nearly above true north. In the Northern Hemisphere, you can find the North Star by tracing a line along the two outermost stars in the Big Dipper—these Pointer Stars are known as Dubhe and Merak—until you hit the nearest bright star. Using this star to navigate will orient you in the direction of true north.

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