Colo. Const. art. I

The boundaries of the state of Colorado shall be as follows: Commencing on the thirty-seventh parallel of north latitude, where the twenty-fifth meridian of longitude west from Washington crosses the same; thence north, on said meridian, to the forty-first parallel of north latitude; thence along said parallel, west, to the thirty-second meridian of longitude west from Washington; thence south, on said meridian, to the thirty-seventh parallel of north latitude; thence along said thirty-seventh parallel of north latitude to the place of beginning.