Clason’s Irrigation Map of Northern Colorado, published by the Clason Map Co. Denver, Colorado. This map was published in 1909 and copyrighted by Geo S. Clason in Denver, CO. This dynamic map outlines irrigation markings as well as topographic features and displays towns and cities such as Denver, Boulder, Larimer, Loveland, Longmont, Platteville, Highland, St. Vrain, among others.