If we use the galactic coordinate system to locate objects within the Galaxy, we can identify the north galactic pole (NGP) as the point where the galactic latitude ( b ) = +90 degrees.
The galactic coordinate system. Positions of objects are measured in terms of their galactic longitude ( l ) and galactic latitude ( b ). The galactic equator slices the Galaxy in half (top and bottom).
The NGP lies along a line that passes through the observer and is perpendicular to the galactic equator. At the other end of this line is the south galactic pole with b = -90 degrees.