Church Rock, a striking stone pillar on Navajo Nation land in northeastern Arizona near Kayenta, rises prominently above Church Rock Valley and stands out as one of the eroded volcanic plugs of the Navajo Volcanic Field. Formed about 30 million years ago during the Oligocene from intrusions and flows of minette and related rocks, it was later shaped by long erosion into an isolated desert landmark. The formation also figured in western travel history: in 1829–1830 Antonio Armijo called it Artenesales de Piedra, or Sculpted Rock, while leading the expedition that established the Armijo Route of the Old Spanish Trail between Santa Fe de Nuevo México and Alta California.