Periodic Spring
About 18 miles south of Afton on U.S. Highway 89

Located 4 miles east of Afton in the Salt River Range, is the largest of three natural springs in the world that naturally turn off and on. Water flow is interrupted from anywhere between 3 to 30 minutes, generally between the months of August-May. It is thought that a cave behind the spring creates a siphon which causes interruption of the water flow. Its ability to turn off and on during low discharge stages has fascinated visitors since prehistoric times. Access to the spring is via the Swift Creek road and requires a 3/4 mile hike by trail.