The Springs

The Springs sits along Highway 21 in Idaho City, a short drive from the Treasure Valley, built around a natural hot springs soaking pool. The main draw is a 2.5-hour general soak session in mineral water that's adjusted seasonally for comfort, with a day pass running $30 for adults. Beyond the main pool, there are private tubs with their own cold-water taps for guests who want to dial in their own temperature, plus a steam room for the full sweat-and-soak routine.

The schedule splits by day: Monday, Thursday and Friday are adults-only (18+), running from 10:30 am to 10 pm with live music some evenings. Saturdays and Sundays are open to all ages until 7 pm, then switch to adults-only from 7:30 to 10 pm. The spa is closed Tuesdays and Wednesdays.

Everything here runs by reservation rather than walk-in, and guest numbers are capped at 65-70 at a time, so booking ahead through the website or by phone is the only reliable way in. A 60-minute therapeutic massage is also available with limited scheduling, and booking one alongside a soak reservation gets a 10% discount on the soak. For anyone extending the trip into an overnight stay, Inn The Pines is about a third of a mile away. Guests driving in from Boise should factor in extra time for ongoing construction near the Mores Creek Bridge on Highway 21, which has been adding delays of 15-20 minutes.