Amboy Crater

Amboy Crater is one of the youngest volcanic features in the broader Mojave volcanic province, which includes a series of cinder cones, lava flows, and small shield volcanoes scattered across the southeastern California desert. The crater itself is a textbook example of a basaltic cinder cone — the symmetrical conical shape was built up by successive eruptions of fragmented basaltic material (cinders, lapilli, and volcanic bombs) that fell back around the central vent and accumulated into the steep-walled cone visible today. The interior of the cone contains a relatively flat-bottomed bowl roughly 1,500 feet in diameter, with the rim rising about 250 feet above the surrounding desert floor and about 150 feet above the bowl floor.

The associated lava field extends across approximately 70 square miles of surrounding desert and includes multiple individual flow units that erupted at various times during the cone's active period. The flows are pahoehoe basalt — relatively fluid lava that produced characteristic ropy and smooth surface textures rather than the jagged blocky textures associated with thicker andesitic lava. Volcanic features visible on the lava field include collapsed lava tubes, pressure ridges, small spatter cones, and scattered volcanic bombs ejected during the cone-building phase.

Dating of the eruptive sequence has been refined over several decades of geological research. Earlier estimates that appear in older Route 66 travel literature suggested an age as recent as 500 to 6,000 years. More recent argon-argon dating and detailed stratigraphic analysis suggest the main eruptive sequence occurred roughly 79,000 years ago, though some surface flows may be substantially younger. For visitors the precise age is less important than the visual impact — the landscape genuinely looks like a recent volcanic terrain, and the contrast between the black basalt flows and the surrounding tan-colored desert is striking.

The standard hiking route starts at the BLM-developed trailhead approximately 3 miles west of Roy's Motel along Old Route 66 (National Trails Highway), with a paved access road leading from the highway to the parking area. The trailhead includes a shaded picnic ramada, vault toilet restrooms, an information kiosk with interpretive signage on the local geology, and a small parking area that accommodates roughly 20 vehicles. There is no fee for parking or access.

From the trailhead, the route crosses a flat sandy desert approach for approximately 1 mile, with the crater visible the entire distance and gradually growing larger as you approach. The trail is well-defined but unpaved, with loose sand in some sections that makes the walking slightly more strenuous than the modest grade suggests. After roughly 1 mile the route reaches the western base of the cone and enters the crater interior through a natural breach in the western wall — the breach is the result of a partial collapse during the eruptive sequence and provides the only practical access to the interior bowl without scrambling.

Inside the bowl the trail continues across the flat crater floor for another roughly 0.25 mile before reaching the base of the rim ascent. The final climb to the rim follows a switchback route up the inside of the eastern wall of the cone, covering about 0.25 mile of distance and 150 feet of vertical gain. The rim itself is narrow in places but generally walkable; visitors who want to circumnavigate the entire rim can do so with another 30-45 minutes of moderate scrambling, though most hikers simply ascend to the rim, photograph the panoramic views, and return via the same route.

The single most important practical consideration for an Amboy Crater hike is the season. Summer temperatures in the eastern Mojave routinely exceed 110°F and frequently reach 115°F to 118°F in July and August. The trail offers no shade — the desert approach and the cone itself are fully exposed — and the dark basalt surfaces absorb and re-radiate heat substantially, producing surface temperatures that can exceed air temperature by 20-30°F. Summer hikers have suffered heat exhaustion and worse on this trail; BLM rangers strongly discourage summer hiking and the trailhead signage carries explicit warnings.

The recommended hiking season is October through April, when daytime temperatures typically range from the 60s to the low 90s. Even within this window, hikers should carry at least 2-3 liters of water per person, wear sun-protective clothing and a hat, apply sunscreen, and start early in the morning when temperatures are coolest. Spring wildflower blooms (typically March and April) can produce surprisingly dense displays of desert annuals across the surrounding lava field during wetter years, and the trail is at its most visually rewarding during these brief bloom windows.

Winter hiking (December through February) is generally the most comfortable timing, with daytime temperatures often in the 50s and 60s and minimal heat risk. Nighttime temperatures can drop below freezing but the daytime hiking window is consistently comfortable. The lava field's dark surfaces look especially striking under low winter sun, and the broader Mojave landscape visible from the rim is at its clearest during winter when atmospheric haze is minimal.

The reward for reaching the rim is a genuinely panoramic view across the eastern Mojave. To the south the Bristol Mountains rise across the surrounding lava field; to the east the Marble Mountains and the broader desert extend toward the Colorado River and Arizona; to the north the I-40 corridor and the surrounding desert basins lead toward the Providence Mountains and the eastern boundary of the Mojave National Preserve. The Amboy townsite itself — including Roy's Motel and the surrounding ghost-town buildings — is visible to the east of the cone from the rim.

The lava field surrounding the cone is the most visually striking element from the rim viewpoint. The contrast between the black basalt flows, the tan-colored surrounding desert, and the white salt pan of Bristol Dry Lake to the southeast produces an unusually graphic landscape that photographs particularly well in low-angle morning or evening light. The full extent of the lava field — covering approximately 70 square miles — becomes evident only from elevated vantage points, and the rim of Amboy Crater is the most accessible such vantage in the area.

Beyond the immediate volcanic landscape, the rim view extends across the broader Mojave Trails National Monument, a 1.6-million-acre BLM-administered conservation unit established in 2016 that includes Amboy Crater along with the larger lava field, the Marble Mountains fossil beds, the Cadiz Dunes, multiple Native American cultural sites, and substantial sections of historic Route 66. The monument designation has improved long-term protection for these resources while keeping public access free.

Amboy Crater pairs naturally with Roy's Motel & Café for a half-day Amboy itinerary. The classic plan for cooler-month visitors: arrive at Roy's by 8am or 9am for morning photography of the Googie sign in good light, drive the few miles west to the Amboy Crater trailhead, hike the 3-mile round-trip route at a relaxed pace (allow 2-3 hours including time at the rim), then return to Roy's for a brief gas-and-water stop before continuing east or west on Route 66. The full sequence runs approximately 4-5 hours and produces a satisfying half-day in the eastern Mojave.

For visitors with more time, the Bristol Dry Lake salt operation visible to the southeast of the crater is an additional point of interest — the salt flats are actively mined by the National Chloride Company of America and have been in commercial operation since the 1910s, though direct visitor access to the salt operation itself is generally limited. The dry-lake surface itself is visible from Old Route 66 and from the crater rim and is photogenic in its own right.

For Route 66 road-trippers continuing west toward Ludlow, Newberry Springs, and Barstow, the crater is the natural last Amboy-area stop. Westbound timing typically puts the crater visit in mid-morning to mid-afternoon depending on the day's overall pace, with onward travel to Ludlow (28 miles west) and Barstow (55 miles west) filling the remainder of the day. Eastbound travelers heading toward Needles can do the crater hike as a morning activity before the longer afternoon drive across the open desert to the Colorado River.