C.R.S. § 38-37-105

(1) For the purpose of providing for and regulating the fees and salaries of public trustees, the said several counties of this state are classified with reference to population and divided into three classes, as follows: (a) Class 1: City and county of Denver; (b) Class 2: Adams, Arapahoe, Boulder, Douglas, El Paso, Jefferson, Larimer, Mesa, Pueblo, and Weld; (c) Class 3: Alamosa, Archuleta, Baca, Bent, city and county of Broomfield, Chaffee, Cheyenne, Clear Creek, Conejos, Costilla, Crowley, Custer, Delta, Dolores, Eagle, Elbert, Fremont, Garfield, Gilpin, Grand, Gunnison, Hinsdale, Huerfano, Jackson, Kiowa, Kit Carson, Lake, La Plata, Las Animas, Lincoln, Logan, Mineral, Moffat, Montezuma, Montrose, Morgan, Otero, Ouray, Park, Phillips, Pitkin, Prowers, Rio Blanco, Rio Grande, Routt, Saguache, San Juan, San Miguel, Sedgwick, Summit, Teller, Washington, and Yuma.