Hot springs in California

California's hot springs follow the state's fault lines — which is to say they're everywhere, from desert seeps to Sierra granite. The San Andreas and its cousins fracture the crust from top to bottom, and where the fractures run deep, hot water rises. The result is the most varied soaking in America: 19th-century bathhouse towns, desert oases, riverside wild pools, and high-Sierra springs you reach on foot.

The historic core is Calistoga, at the top of Napa Valley, where the Wappo people soaked long before the railroad arrived and where a row of resorts still offers mud baths and mineral pools in buildings older than the state park system. The Central Coast (Avila Beach) and the inland valleys (Corona's Glen Ivy, the Ojai-adjacent Sespe wilderness) cover the south-central springs. The Eastern Sierra — Mammoth, Bridgeport — pairs wild roadside pools with some of the most photographed soaking in the country, all of it free and all of it first-come.

The desert springs are their own world. Tecopa, near Death Valley, is a tiny town built around hot water, with a county-run free bathhouse and a classic desert resort. Desert Hot Springs, outside Palm Springs, sits on an aquifer so mineral-rich that the town's mid-century hotels were built around it. And the Kern River canyon hides wild pools — Remington, Miracle — a short scramble from the road.

Then there's the north: Wilbur's historic resort in the Capay Valley, Orr's redwood-shaded retreat near Ukiah, Sierra Hot Springs' temple-like bathhouse near Sierraville, and Grover's state-park pools near Markleeville. Practical notes: California wild springs demand the most caution — check road and fire-closure conditions (forest closures are common in fire season), carry more water than you think, and know that desert springs are dawn-or-dusk destinations in summer. Developed resorts book out on weekends; wild pools are weekday mornings' reward.