Spas with thermal pool

Ramona, California

A vacation-rental resort in Ramona whose day-spa access, sauna, steam room and heated pool are reserved for guests staying on the property.

Calistoga, California

MoonAcre Spa & Baths is a day spa in Calistoga with a thermal pool, hot tub and sauna, open daily 9am–5pm and geared toward families and couples.

Taos, New Mexico

A moderate-priced day spa at Taos Ski Valley with a heated pool, hot tubs, steam rooms and a day pass open to non-hotel guests.