C.R.S. § 3-1-124

From and after the delivery of such deed of cession, the said site and erections, structures, buildings, fixtures, goods, chattels, and property, at any time thereon or thereto belonging or in any wise appertaining and belonging to the United States, shall be and remain released and exempt from all tollages, taxes, and assessments, of every name and nature, for and during the time the United States shall remain the owner thereof.