Geothermal springs are, literally, hot tub time machines. Formed millions of years ago, these naturally occurring formations bubble out from deep within the earth at temperatures that can range from pleasantly lukewarm all the way to boiling hot. And while they may be related to gushing geysers like Old Faithful, don’t worry: Around the country, there are plenty to soak in—the National Centers for Environmental Information counts some 1600-plus—that won’t, well, shoot you 50 feet into the air or literally melt your face off.
For centuries before the naturopathic-crystal-Goop industry took off, hot springs were the cure for tired muscles and hike-weary legs; they’ve long been known for containing healing minerals like calcium carbonate and magnesium sodium sulfate. (Scan the label on a package of bougie mineral bath salts and you’ll see the same ingredients.)
They can be rustic or resort-chic, perfect for a luxe solo soak or an energetic bachelorette party. You can find them on public land, in national parks, or even in resorts, restaurants, and—praise be—bars. Some require hiking boots and a map; others just a credit card. No matter what vibe you’re after, sinking into a pool of restorative thermal water is a surefire way to soak your winter blues away.