The Long Valley of Utah is a 13-mile (21 km) long valley located in western Kane County. The valley is located in source water regions of waters flowing north, south, and southwest, in the west of the section of the Colorado Plateau; the High Plateaus section also extends into northern Arizona, the region north of the Grand Canyon. The East Fork Virgin River flows due-south, from near the valley center, then just south of Glendale, the river starts its southwesterly course. The sourcewaters are in the valley's northeast terminus region in the Long Valley Junction area.