The state highway system in the U.S. State of Colorado is comprised of State Highways (typically abbreviated SH), U.S. Routes, and Interstate Highways. The numbered highways begin at 1 and increase, with exception of numbers already designated as U.S. highways or Interstate Highways with the state. As a consequence, there are no state highways in Colorado designated as 6, 24, 25, 34, 36, 40, 50, 70, 76, 84, 85, 87, 138, 160, 225, 270, 285, 287, 350, 385, 400, 491, or 550.