Ariz. Rev. Stat. § 11-105
Coconino county, the county seat of which is Flagstaff, is bounded as follows:
Commencing at the point where the boundary line between Utah and Arizona, being approximately the thirty-seventh parallel of north latitude and the meridian of one hundred ten degrees forty-five minutes west longitude intersect; thence south along such meridian to the Mogollon Rim; thence westerly along the Mogollon Rim, and the northern boundary of Gila county to the east line of range seven east, Gila and Salt River Guide meridian; thence north on such range line to the fourth standard parallel north; thence west on such parallel to the east line of range five east; thence north on such range line to the north line of township eighteen north; thence west on such line to the Gila and Salt river meridian; thence north on such meridian to the fifth standard parallel north; thence west on such parallel to the east line of range two west; thence north on such line to a point one mile north of the center of the right-of-way of the Atchison, Topeka & Santa Fe railway as it existed in 1891; thence westerly in a line one mile north of and parallel with the center of such right-of-way to the meridian one hundred thirteen degrees twenty minutes west longitude, as defined by the Mohave-Yavapai county boundary survey of 1908; thence north along such meridian line as defined to the point where such meridian line intersects the Colorado river; thence up the centerline of the Colorado river to the mouth of Kanab creek; thence up Kanab creek to a point where such creek intersects the boundary line between Utah and Arizona, being approximately the thirty-seventh parallel of north latitude; thence east along such boundary to its intersection with the meridian of one hundred ten degrees forty-five minutes west longitude, the place of beginning.
A.R.S. § 11-105