Amboy Crater formed through explosive volcanic activity that began approximately 79,000 years ago and continued sporadically until about 10,000 years ago. The crater itself is a cinder cone - built from accumulated volcanic debris ejected during eruptions - while the surrounding lava flows represent later, quieter eruptions that poured basalt across the desert. The Bristol Lake Volcanic Field, of which Amboy is part, lies along fault lines associated with the San Andreas system. The volcano is dormant, not extinct; geologists consider future eruptions possible though not imminent. The perfect cone shape results from winds during eruption consistently blowing debris to the west.

Amboy existed to serve Route 66 travelers crossing the Mojave. At its peak, the town offered Roy's Motel and Café, a gas station, a school, a church, and a post office - everything a mid-century motorist needed. When Interstate 40 bypassed the town in 1973, Amboy began dying. By the 2000s, the population was four. Roy's Café, with its iconic Google-style sign, has been restored as a nostalgic pit stop and photo opportunity. The rest of Amboy is essentially abandoned, a ghost town in the shadow of its volcano. The juxtaposition is perfect: Route 66 Americana meets geological violence.

The lava field surrounding Amboy Crater covers 70 square miles of black basalt, one of the youngest lava flows in the Mojave. Pressure ridges and lava tubes create complex terrain; some tubes are large enough to enter. The black rock absorbs heat; summer temperatures in the lava field can exceed 130°F at ground level. Life persists - creosote bushes colonize cracks, lizards hunt insects - but the impression is extraterrestrial. The resemblance to lunar landscapes made it a dramatic filming location; HBO's 'From the Earth to the Moon' featured the crater in its Apollo 15 episode. Actual NASA astronaut training occurred at similar sites including Craters of the Moon in Idaho and Cinder Lakes near Flagstaff.

Hiking to Amboy Crater's rim requires 1.5 miles through the lava field on a well-marked trail. The ascent up the crater's flank is steep but short. At the rim, the interior is visible - a bowl 500 feet across with a small secondary cone inside. A breach in the rim allows descent into the crater itself. The experience is visceral: standing inside a volcano, surrounded by cinders and silence, understanding viscerally that this ground was molten within human prehistory. The Mojave heat intensifies everything. This is not a casual hike; it's a confrontation with geological power.

Amboy Crater is located off National Trails Highway (old Route 66), approximately 75 miles east of Barstow, California. The crater is managed by the BLM as Amboy Crater National Natural Landmark. A parking area provides trailhead access; no facilities exist on site. The hike is 3 miles round trip with 250 feet elevation gain. Bring abundant water - at least one gallon per person in summer. Avoid hiking during peak summer heat; morning visits are essential. The ghost town of Amboy offers limited services; Roy's Café provides gas and snacks when open. Twentynine Palms or Barstow offer full services. The isolation is genuine; plan accordingly.