As explained in Starstruck Tonight:
From ancient times sailors have known that the altitude of Polaris above the horizon is the same as one's latitude on Earth. Our latitude in Shawnee is 35 degrees north, and we find Polaris 35 degrees above the northern horizon. Similarly, to sail west at a constant latitude Columbus kept the north star at a constant altitude above the horizon.
Confirm the altitude of Polaris above your northerly horizon with a protractor quadrant!