New Mexico Statutes Chapter 4. Counties § 4-18-2. Northwest boundary with Taos county

The boundaries dividing the counties of Taos and Mora shall hereafter be as follows, that is to say: west of the valley of Mora, a line running north, commencing at the first hill west of the said valley of Mora, and east of the Jicarita, crossing the Vega del Estillero opposite Canada del Raton, passing through the said canada till it reaches the foot of the Osha hill on the western base thereof; thence continuing north along the eastern base of said range, along the eastern side of the head of the Rio Colorado which runs into the Rio Grande in the county of Taos, and thence in a northeast direction to the limits of the territory of New Mexico and the territory of Colorado.