The hikers that summit this mountain each year are treated to "exceptional" views of Lassen Peak,[3] the Central Valley of California, and many of the park's other features.

Brokeoff Volcano was active from 590,000 to 387,000 years ago, during which period it erupted numerous flows with compositions ranging from basaltic andesite to dacite.

At its peak, Brokeoff Volcano reached an estimated height of 3,350 metres (10,990 ft) and had a basal circumference of approximately 12 kilometres (7.5 mi).

These hydrothermal fluids chemically weathered the volcanic rocks near the central vent, making them particularly susceptible to physical erosion.

In May 1907, Lassen Peak was declared a national monument by President Theodore Roosevelt to protect the area for "future generations to study and enjoy".

Eruptions varied from ejection of pyroclastic material to andesitic lava flows built primarily of feldspar, pyroxene, and olivine.

One additional and final vent formed on the northeastern flank of the volcano, erupting glassy dacitic flows.

[7] Over time, the volcano became dilapidated from extensive erosion and hydrothermal alteration,[6] and was eroded by creeks and glaciers.

After volcanism at Brokeoff ended, magmatism became more silicic and began migrating toward Lassen Peak's northern flank.

A subsequent explosive eruption ejected 12 cu mi (50 km3) of material and created a large crater, which was soon covered by lava.

[9] Near the trailhead at lower elevations, alder thickets are present, as well as incense cedar, red firs, and western white pine.

[8] In addition to the volcanic hazards that could possibly occur, one volcano did erupt in the 20th century in LVNP: (Lassen Peak).