In 1928, almost none of US 66 was paved in Arizona, save for a stretch of highway between Flagstaff and Winona. This section had been paved back in 1921 with concrete mixed with locally sourced volcanic cinder. The highway was given a non-paved secondary surfacing (another term for gravel surfacing) between the Colorado River and east of Peach Springs. A section of US 66 from Crookton through Ash Fork to Williams was also paved in secondary surfacing. This section was approximately long. Secondary surfacing was also extant on a section of highway running from Bellemont to Flagstaff, as well as a section between Meteor Mountain (just east of Canyon Diablo) and Holbrook. The remainder of US 66 was graded, but had no improved surfacing of any kind.