If using a compass in the Rockey Mountains, what would the megnetic declination be, or would it be unaffected?

Question

Is it? 1. West of true north
2. East of true north
3. Unaffected

Answer 1

Magnetic declination is the angle between the direction to the earth's rotational axis and the magnetic north pole. In other words, declination is the difference between true north (astronomic or axial, almost the same) and magnetic north (the direction the compass points). In North America (except in the extreme north), both of these points are in the same direction (or a zero declination) in an approximate north-south line running just west of the Great Lakes roughly following the Mississippi River. Because the earth's north rotational axis is north of the magnetic north pole (by "true" direction), all points lying west of that line have an "east" or "positive" declination, and points to the east have a "west" or "negative" declination.

The declination in the Rocky (not Rockey) Mountains is east of true north. It would vary from about 15°E in the southern Rocky Mountains in Colorado to about 35°E in Yukon. You would have to know what part of the Rockies you are in to give a better answer.

Answer 2

Located on the bottom of all USGS topo maps is the declination of the area the map covers
"GN" is geographic north "MN "is magnetic north