The route was established in the 1920s, when SH 133 began at SH 135 in Bardine and ended at Carbondale. SH 133 was then reroutes from SH 135 at Crested Butte to Carbondale by 1936. The route's south terminus was adjusted back to Bardine in 1939, and a small gap at McClure pass was opened. By 1954, a large section of the route was deleted, leaving only a four-mile (6 km) road near Carbondale. The route was gradually expanded through the late 1950s and early 1960s. The route was entirely paved by 1978.