Utah-Arizona State Line Elevation: 4,960 ft. Southern end of Utah Highway US 191 on the Arizona-Utah State Line, 5 miles north of the junction with Arizona Highway US 160 (1.6 miles east of Mexican Water and 30 miles west of Teec Nos Pos and nearby Four Corners Monument). The first 20 miles travel through the Navajo Indian Reservation. Utah Highway US 191 is southeastern Utahs main artery, interlinking beautifully sculpted canyons, breathtaking red rock formations, majestic snow-capped mountain peaks, rugged and colorful high desert beauty, geological treasures, mysterious prehistoric ruins and rock art, historic sites, a myriad of recreational opportunities and old-fashioned western hospitality.