Pearsoll Peak rises in the Klamath Mountains of southwestern Oregon as the highest point in the Kalmiopsis Wilderness, in remote backcountry not far from the Pacific coast and the California line. Its most notable feature is a historic fire lookout overlooking the Illinois River Valley. The current L-4 lookout cabin replaced an earlier cupola-style structure in 1954 and was staffed into the early 1970s before falling into disrepair. Restored in 1991 by the Sand Mountain Society, it has been carefully maintained since. The lookout survived the Biscuit, Chetco Bar, and Klondike fires, making the peak important for both its landscape and its conservation history.