Colorado Revised Statutes Title 35. Agriculture § 35-47-101. Horses and mules running at large

It is unlawful for any owner, or the agent, lessee, bailee, or employee of such owner of any horses or mules, to knowingly permit any of said animals to run at large, within a distance of ten miles from any city having one hundred thousand or more population; within a distance of five miles of any city having between five thousand and thirty thousand population; within a distance of one mile of all other cities or towns; and within a distance of one mile from the business area of any unincorporated town or village; but nothing in this article shall prevent anyone from driving any of said animals to market or from pasture to pasture or prevent the use of horses or mules for riding, driving, or drawing animal-propelled vehicles or machinery. This article shall not affect any common used solely for grazing purposes which has been established by land grant and ratified by treaty.