Deer Creek flows approximately 60 miles through Tehama County from near the summit of Butt Mountain at roughly 7,320 feet elevation through meadows and dense forests before emerging onto the Sacramento Valley floor. This eastside tributary to the Sacramento River represents one of California's last intact ecosystems, remaining undammed and free-flowing along most of its length. As one of only three remaining Sacramento River tributaries supporting genetically distinct Central Valley spring-run Chinook salmon, Deer Creek serves as a critical conservation stronghold. The creek's diverse habitats include ponderosa forests, grasslands, oak savannah, and chaparral in the upper reaches, transitioning to valley floor pools and riffles downstream. The watershed flows through the remote Ishi Wilderness and supports important winter range for the Tehama black-tailed deer herd—the largest migratory deer herd in California.