Entry No. 9 — the Missoula file — filed under: soak

Nimrod Warm Springs

This is a completely undeveloped warm spring on private land where the family owners quietly allow respectful free access. The water hovers around 70 degrees year-round, more refreshing soak than scalding hot tub, in a wild riverside setting. Its strangest feature is an underwater cave you can dive down to and surface inside, a trick reserved for confident swimmers who bring goggles or a light for the murky visibility. There are no facilities, no signs, and no staff, just a genuinely odd natural pool that locals work hard to keep open.

The move: Drive out on a warm afternoon for a low-key wild soak, and if you are strong swimmers, take turns ducking down to the hidden underwater cave.

📍 Before you go On private property; access is a courtesy, so pack out everything and be respectful or access may close. The underwater cave is for expert swimmers only. Water is warm (~70F), not hot; no facilities of any kind.

• 📍 Nimrod / Bearmouth (east of Missoula)
• 💸 Free
• ⚡ Up for anything
• 🌗 Outdoors

Where: Near Nimrod, off I-90, Granite County, MT

Hours: Added 2026-06-24 — confirm current hours before you go.

⚠ Seasonal or scheduled — always check before you go.

Plan a visit & invite your people →

Proof: source 1 · source 2 · source 3 · source 4

last checked: 2026-06-24