Sunset Crater Volcano National Monument

Around 1085 AD — roughly the time William the Conqueror's sons were fighting over England — a fissure opened in the earth 12 miles north of present-day Flagstaff. Molten basalt erupted from the vent, fountaining hundreds of feet into the air and raining down as cinder, ash, and volcanic bombs. Over the next several decades, the eruption built a symmetrical cinder cone that eventually reached 1,000 feet above the surrounding terrain. Lava flows poured from the base of the cone, spreading across the landscape in thick sheets of basalt.

The eruption was not a single catastrophic event but a prolonged process. The Sinagua people who farmed the area evacuated their pithouses (archaeological evidence shows an orderly departure, not a panicked flight) and relocated to areas beyond the fallout zone. But the eruption's aftermath produced an unexpected benefit: the thin layer of volcanic cinder that blanketed the surrounding terrain acted as a moisture-retaining mulch. Rain and snowmelt soaked into the porous cinder instead of evaporating, making previously marginal farmland productive. Within a generation, communities began to resettle the area — and the population at Wupatki, 20 miles to the north, exploded.

The name "Sunset Crater" comes from the red and orange oxidized cinders near the rim, which give the upper slopes a sunset-like glow, particularly in late afternoon light. The explorer John Wesley Powell named it during an 1892 expedition.

The Lava Flow Trail is a 1-mile paved loop that takes you directly through the Bonito Lava Flow at the base of Sunset Crater. This is the highlight of the monument and one of the most accessible lava field walks in the American West. The trail is flat, well-maintained, and wheelchair accessible for most of its length, with interpretive signs every few hundred feet explaining what you are seeing.

What You Walk Through

The trail passes through two distinct types of lava. Aa lava (pronounced "ah-ah") is the rough, jagged, blocky type — it looks like a field of broken black glass and concrete rubble. Walking next to it, you understand why Hawaiian geologists named it "aa" — reportedly the sound you make if you try to walk across it barefoot. Pahoehoe lava (pronounced "pa-HOY-hoy") is smoother, with a ropey, swirled surface that formed when the outer crust of flowing lava folded over itself. The contrast between the two types is dramatic, and the trail gives you close-up views of both.

Along the trail, you pass lava squeeze-ups (places where semi-molten lava was forced through cracks in the hardened surface), lava tubes (collapsed underground channels where lava once flowed), and volcanic bombs (blobs of molten rock that were thrown into the air and solidified mid-flight into aerodynamic shapes). Several interpretive stops have cross-section views into the lava showing the internal structure — layers, bubbles, and flow patterns frozen in time.

Trail Conditions and Tips

The trail is paved and mostly flat, but a few sections have gentle inclines. Allow 30 to 45 minutes for a comfortable pace with stops to read the interpretive signs. Key tips:

• Bring a windbreaker — the lava field is completely exposed, with no trees or shelter. Wind can be fierce, especially in spring, and the temperature on the trail can feel 10 to 15 degrees cooler than the parking lot when wind is blowing.
• Stay on the trail — the lava is sharp and brittle. Stepping off the trail damages fragile lava formations and the biological soil crusts (dark, crusty patches of cyanobacteria and moss) that have taken centuries to develop. It can also cut through hiking boots and skin.
• Morning light is best — the low-angle sun creates strong shadows that emphasize the texture of the lava surfaces. By midday, the black rock absorbs intense heat and the flat light reduces visual contrast.
• Watch for lava tube openings — several collapsed tubes are visible from the trail. Do not climb into them — they are fragile and can be deeper than they appear.

If you want to know what it feels like to climb a cinder cone — since Sunset Crater itself is closed — the Lenox Crater Trail provides that experience on a smaller, more resilient cone nearby. The trail is a 1-mile round trip that climbs about 280 feet to the rim of Lenox Crater, a small cinder cone adjacent to the main loop road.

The climb is short but genuinely strenuous. The trail surface is loose volcanic cinder — like climbing a steep hill of gravel. For every two steps forward, you slide back one. Good traction footwear is essential. The ascent takes 20 to 30 minutes for most hikers. At the top, you are rewarded with a view into the shallow crater and a panoramic perspective of Sunset Crater, the lava fields, and the San Francisco Peaks to the west.

This trail is the best option for visitors who want a physical challenge and a summit view. It is also the best place to experience the texture and color of volcanic cinder up close — the dark black and red fragments crunch underfoot and shift with every step. Kids old enough for a moderate hike (roughly age 8 and up) generally love the novelty of climbing on volcanic debris.

Why You Cannot Climb Sunset Crater

Sunset Crater was open to hikers until 1973. By that year, the foot traffic had carved deep erosion channels into the cinder slopes, and the crater's symmetric profile — formed over decades of eruption and preserved for 900 years — was visibly deforming. The National Park Service closed the crater to all foot traffic to prevent further damage. The cinder is extremely loose and fragile; even a single hiker displaces material that takes centuries to stabilize naturally. Lenox Crater, being smaller and more compact, handles foot traffic better and provides a similar experience.

The Bonito Lava Flow is the most prominent lava field visible from the loop road. It spread from the base of Sunset Crater to the west, filling the Bonito Park area with a thick sheet of basalt. The flow is roughly 2 miles long and up to 100 feet thick in places. From the road, it looks like a frozen black sea — its surface is buckled, cracked, and contorted into shapes that suggest tremendous force frozen in mid-motion.

Several pullouts along the loop road provide views of the lava flow and the cinder cone. The most notable:

• Bonito Lava Flow Overlook — just past the visitor center, with interpretive panels and the best view of the flow's full extent against the crater backdrop.
• Painted Desert Vista — farther north on the loop road, where the landscape transitions from lava field to desert grassland. On clear days, you can see the Painted Desert stretching to the northeast and the distant Hopi mesas.
• O'Leary Peak Road — a rough dirt road (high-clearance vehicles recommended) that branches off the main loop and climbs to a fire lookout tower with a commanding view of the entire volcanic field. This is a side trip, not part of the main loop, and adds 30 to 45 minutes.

The scenic loop road (Forest Road 545) connects Sunset Crater and Wupatki National Monument in a one-way drive that ranks among the best scenic routes near Flagstaff. Most visitors enter at the south end (Sunset Crater side), 12 miles north of Flagstaff on US-89, and exit at the north end near Wupatki, 25 miles north of Flagstaff on US-89.

The landscape transformation along the drive is remarkable. You begin in ponderosa pine forest, descend into black lava fields dotted with cinder cones, pass through a transitional zone of juniper and desert scrub, and emerge into the open painted desert grasslands around Wupatki. The elevation drops from about 7,000 feet at Sunset Crater to 4,900 feet at Wupatki, and the vegetation, light, and atmosphere change completely.

The road is paved, two-lane, and suitable for any vehicle. There are no gas stations, food, or water along the 36-mile route — fill up and pack snacks before leaving Flagstaff. Cell service is spotty to nonexistent. Budget 3 to 4 hours for the full loop with stops at both monuments, or 1.5 to 2 hours if you only stop at Sunset Crater's main attractions.

• Wear closed-toe shoes with good soles — the lava is sharp and will shred sandals. Even on the paved trail, the edges of the lava flow are close enough to scrape exposed skin if you stumble.
• Sunscreen and hat are essential — the lava field has zero shade. The black rock absorbs and re-radiates heat, making the trail feel hotter than the ambient temperature. UV exposure at 7,000 feet is intense.
• Water — carry at least one liter per person. The visitor center has water, but there is none on the trails or elsewhere in the monument.
• Binoculars — useful for studying the Sunset Crater rim details (the red and orange oxidized cinders are most visible through magnification) and for spotting wildlife. Hawks, ravens, and the occasional pronghorn are common.
• Do not collect — it is illegal to remove rocks, cinder, lava, or any natural material from the monument. This is strictly enforced. The volcanic material looks tempting as a souvenir, but every piece removed degrades the site.
• Pets — allowed in parking areas only. Not permitted on trails. The black lava absorbs extreme heat that can burn paw pads, even on mild days.
• Lightning danger — the lava field is flat and exposed with no shelter. If thunderstorms develop (common July-September afternoons), return to your vehicle immediately. Do not shelter under isolated trees at the lava flow edge.

Morning visits are best in every season. The low-angle light creates dramatic shadows and textures on the lava surfaces, the temperatures are cooler, and the wind is typically calmer. By midday in summer, the black lava absorbs intense heat and the experience becomes uncomfortable. In monsoon season (July-September), morning visits also avoid the afternoon thunderstorm risk.

Spring and fall offer the best overall conditions — comfortable temperatures, clear skies, and the seasonal light shifts that make the volcanic landscape most photogenic. Late October through November can be spectacular when the aspens on the nearby San Francisco Peaks turn gold, providing a dramatic color contrast against the black lava.

Winter visits are possible and often uncrowded. Snow on the lava field creates striking visual contrast — black rock against white snow — and the air is crystal clear. However, the Lava Flow Trail may have icy patches, and the Lenox Crater Trail can be slippery when snow-covered. The loop road remains open year-round barring heavy snow.

The Sunset Crater Visitor Center sits near the south entrance on the loop road. Inside, exhibits explain the eruption sequence, the types of lava (with samples you can touch), the impact on the Sinagua population, and the ongoing geological activity in the San Francisco Volcanic Field. A short film provides an overview of the eruption and its regional consequences. Rangers are available to answer questions and can provide Junior Ranger booklets for kids.

Restrooms are available at the visitor center. There are no restrooms on the trails or elsewhere along the Sunset Crater portion of the loop road. The Wupatki visitor center, 20 miles north on the loop road, has additional restrooms.

The entrance fee ($25 per vehicle) is collected at the entrance station just south of the visitor center. If you have an America the Beautiful pass, show it here. The receipt covers both Sunset Crater and Wupatki for 7 days.