The trailhead for Lassen Peak sits high on the park road, at about 8,500 feet, and above it the mountain rises another two thousand feet in a single, slightly crumpled dome of grey rock. Lassen is one of the largest plug-dome volcanoes in the world, and it is also the southernmost active volcano in the Cascade Range, the chain that runs north through Oregon and Washington to Mount St Helens and beyond. It looks quiet now, but that is a deception, as the ground at its feet bubbles and steams.
The summit trail climbs in switchbacks across scree and loose rock, around five miles for the round trip, with views widening at every turn to Lake Almanor and the Sacramento Valley, and on clear days Mount Shasta, far to the north. It is steep and exposed, and the thin air makes it harder than it looks, so many people find it takes most of a day. Snow lingers on the upper trail into summer, and thunderstorms can build quickly in the afternoon, so start early and turn back if clouds gather.
The mountain's history is dramatic. In 1914, after a long quiet period, it began erupting, with blasts of steam and ash, and in May 1915 a larger eruption flattened trees and sent a mudflow down the valleys, and a huge plume of ash rose miles into the air. Eruptions continued until 1917, and the damage can still be seen in the area known as the Devastated Area, where boulders carried by the mudflow lie scattered among regrowing forest. The park was created in 1916, partly because of the interest in the eruptions.
The road to the trailhead is a fine one, a smooth, curving climb through fir forest, with views of lakes and meadows, steady gradients and little traffic, especially early in the day. It is usually open only from early summer to late autumn, as snow can bury it for months, and you should check the status in advance. Wildlife includes deer, marmots and black bears, and the wildflowers bloom in July.
Services at the trailhead are limited to toilets and a car park, and fuel is available only outside the park. Chester and Shingletown are the nearest towns with stations, about thirty kilometres away, so arrive with a full tank, water and warm clothing.
Look at the summit before you decide whether to walk it. The mountain is honest about what it asks.