Trinity Site Travel Planner
Trinity Site is where the first atomic bomb was tested at 5:29:45 a.m. Mountain Time on July 16, 1945. The 19-kiloton explosion not only led to a quick end to the war in the Pacific but also ushered the world into the atomic age. All life on Earth has been touched by the event which took place here.

The 51,500-acre area was declared a national historic landmark in 1975. The landmark includes base camp, where the scientists and support group lived; ground zero, where the bomb was placed for the explosion; and the McDonald ranch house,where the plutonium core to the bomb was assembled. Visitors to a Trinity Site Open House see ground zero and the McDonald ranch house. In addition, one of the old instrumentation bunkers is visible beside the road just west of ground zero.
Note: The site is open twice per year on the first Saturday in April and October. No reservations are required.