Let's talk about magnetic north. As seen in the map above it varies from true north by the indicated amounts across the country. Magnetic north is constantly changing, albeit small amounts. In Las Vegas, 1995, magnetic north was about 11 degrees east of north. I have USGS maps from the 80's which put the magnetic declination for Taos at around 13 degrees, so apparently it changed a degree or so in a couple decades.
Anyway, barring big iron deposits on the ranch, in Denver a compass will read about 10 degrees to the east of true north. So, lay out your compass and true north is about 10 degrees to the west (or 10 degrees counter-clockwise).
Click to get current magnetic north.
What is true north? That's the direction in which the northern pole of the earth points.
And what is the pole of the earth? It's the rotational axis around which the earth rotates.
And where does it point? Directly at the North Star, which is why it's also called Polaris--the Pole Star. The North Star isn't exactly in line with our rotational axis, it's off maybe a half degree or so-- but close enough that we rarely notice it.
In the end, using the North Star to get true north is a better method than using a compass and interpolating because of all the things (stray fields, buried bits of steel, etc.) which can effect a compass.