Bureau of Land Management, California.
Amboy Crater was designated a National Natural Landmark in 1973 and is recognized for its visual and geological significance. Amboy Crater is an example of a very symmetrical volcanic cinder cone. There is a breach on the west side of the crater where basaltic lava poured out over a vast area of 24 square miles, which contains lava lakes, collapsed lava tubes and sinks, spatter cones and massive flows of basalt. Amboy Crater lies about halfway between Barstow and Needles (about 66 miles from each) off Historic Route 66 National Trails Highway.
From Needles, CA, take I-40 west approx. 65 miles to Kelbaker Road. Exit southbound on Kelbaker Road and drive approx. 10 miles to National Trails Highway. Turn left on National Trails Highway and drive approx. 8 miles to Crater Road. Turn left onto Crater Road. An entrance kiosk will be on your left hand side.