Las Llajas Canyon in northeastern Simi Valley is an open-space canyon in the Santa Susana Mountains valued for both recreation and wildlife habitat. Its landscape of rolling hills, rock formations, oak trees, and a creek supports hiking, biking, horseback riding, climbing, and links to other public lands. Geologically, the canyon dates to the Eocene Epoch and was cut into marine sediment where fossils have been found, though this terrain also makes it prone to floods and landslides. A planned recreational lake from the 1970s survives as a debris basin. The canyon also holds traces of local history, including the former Pisgah Grande religious colony and a name adopted in 1931.