Alkali Lake Hot Springs
By the HotSpringsFind editorial team · How we compile records · Reviewed September 2026
Alkali Lake Hot Springs is a primitive hot spring listed near Mammoth Lakes, California. Reported soak temperature: 115°F. See the visit fact sheet.
Stop on Highway 395 Hot Springs — see all stops, ordered south to north.
Current status
Primitive roadside geothermal source by Little Alkali/Warm Lake off paved Benton Crossing Road near Mammoth Lakes (BLM land); the small volunteer-built concrete-slab tub fed by PVC pipe is often plugged, dry, or scalding — nearby Hilltop (Pulky's) tub is the reliable soak.
Checked June 2024 · based on recent visitor reports · 5 sources ↓
Staying overnight?
Choose town lodging for the Long Valley springs reached from US-395 and Benton Crossing Road.
Mammoth Lakes is about 11 mi from the spring (straight line).
We may earn a commission from bookings through these links, at no extra cost to you.
Before you go
- Status: Open — last verified below — confirm via Hot Springs Locator — Alkali Lake Hot Springs (135F source, pipe-fed tub, 'does not provide the best soaking').
- Cost: Reported free access — fees and permits can change, confirm before visiting.
- Getting there: No verified hike distance on record — confirm the route and road conditions.
- Water: Reported soak temperature 115°F — always test the water before entering.
- Rules: Reported clothing-optional; pets reported not allowed — confirm current rules.
- Conditions: check weather, fire closures, and land-manager alerts the week you go — mountain access changes seasonally.
- Reservations/permits: None — BLM public land.
- Best time to go: Year-round accessible (beside paved road); winter soaking is popular but the dirt spur may be snowed in — park at the gate and walk.
- Clothing reality: No official rule; clothing-optional custom on all Long Valley BLM springs; this exposed roadside spot is in view of passing traffic.
- Kids: Allowed.
- Cell service: spotty — download maps and tell someone your plan.
- Accessibility: Short flat walk when gate open; no facilities; tub is primitive.
- Pool reliability is poor: ~120-135F source in a corrugated metal culvert feeds a shallow 5-ft concrete-slab tub via PVC pipe — pipe has been found plugged and the pool dry (documented 2007; still reported marginal), and when running it is often too hot to enter
- NAMING OVERLAP: OpenStreetMap labels this area 'Alkali Hot Springs' and directories conflate it with Hilltop Hot Spring (Pulky's Pool) — the famous reliable tub on the hill ~0.25-0.5 mi SE with valve-adjustable 100-110F water
- Free BLM land (Bishop Field Office); no fee, no permit, day-use custom; no camping at the spring but dispersed camping allowed on nearby BLM land
- Access: US-395 to Benton Crossing Rd (paved) ~4.4 mi, then short dirt road to a gate near the lake — when the gate is closed it's ~0.6 mi walk; dirt section can be muddy/snowy
- Exposed site — visible from the paved road; little privacy
- ~13 mi east of Mammoth Lakes; nearest campground Brown's Owens River ~2.5 mi
- Hazard: 120-135F source water; tub can be scalding or dry
- Hazard: Exposed roadside site
- Hazard: Winter snow/mud on dirt spur
- Hazard: Rattlesnakes in warm months
About this spring
Hot spring in the Long Valley Caldera ~13 mi east of Mammoth Lakes on BLM land, next to Warm Lake near Big Alkali Lake. Water (~135°F source) is piped ~50 ft to a shallow concrete tub — often still too hot to soak; quality inconsistent (tub sometimes dry when the feed pipe is plugged). Often too hot to enter — test first. Pool may be dry. Exposed site. No facilities.
Alkali Lake Hot Spring is one of several soaking spots in the Hot Creek geothermal area of the Long Valley Caldera, on BLM-managed land east of Mammoth Lakes, named for the adjacent dry lakebed near Benton Crossing Road. A single source of roughly 120°F water is captured by a galvanized metal culvert sunk around the vent, and a PVC pipe carries it to a shallow, roughly five-foot-diameter pool dug into the ground and lined with concrete slabs. The catch is reliability: the feed pipe is easily plugged and the pool has repeatedly been found dry — a spring 2007 report described exactly that — and when the piping does work, the delivered water tends to run too hot to soak comfortably; an earlier bathtub beside the pool is also described in older accounts. The tub sits within sight of a paved, maintained road, so it is accessible even in snow but fully exposed to view. No camping is allowed at the site and there are no facilities — an erratic footnote to the better-known Long Valley tubs nearby.
Directions & trailhead access
Benton Crossing Road ~4.4 mi from US-395 to a small dirt road and gate near the lake; tub ~100 yards from parking.
California geothermal context
California spans several geothermal provinces: the volcanic Cascades and Modoc Plateau in the northeast, Sierra Nevada granite seeps along the eastern front, Mojave and Colorado Desert springs in the south, and the famously mineral-rich Big Sur coast. Fire season (roughly June–November) closes access to many backcountry springs without warning — always check for current fire restrictions.
What a primitive site means here
Primitive springs have no facilities: no changing rooms, no trash service, often no maintained road to the pool. Expect natural rock or gravel bottoms, water temperature that varies by spot and season, and other visitors who may treat the site informally. Pack out everything you bring, test the water before entering, and leave the pool cleaner than you found it.
Best time to visit
Year-Round (Best: May – October)Pool temperatures and access can change with weather and season. Outdoor ambient temperatures fluctuate significantly across California. Late spring through autumn offers the most comfortable road access.
Fact sheet
| Reported soak temp | 115°F |
|---|---|
| Source temp (historical) | 135°F |
| Trail access | Recorded coordinates — access unverified |
| Access fee | Reported free — verify locally |
| Clothing policy | Reported clothing-optional |
| Pet policy | Reported no pets |
| Geothermal data reference | NOAA Thermal Springs List (1980 archive) |
| Check land status | Hot Springs Locator — Alkali Lake Hot Springs (135F source, pipe-fed tub, 'does not provide the best soaking') |
Alkali Lake Hot Springs FAQ
Is Alkali Lake Hot Springs open right now?
Primitive roadside geothermal source by Little Alkali/Warm Lake off paved Benton Crossing Road near Mammoth Lakes (BLM land); the small volunteer-built concrete-slab tub fed by PVC pipe is often plugged, dry, or scalding — nearby Hilltop (Pulky's) tub is the reliable soak. (Status based on recent visitor reports, last checked June 2024.)
Is Alkali Lake Hot Springs free?
Alkali Lake Hot Springs is listed as free to access in Mono County, California. Fees and rules change — verify current status with the land manager before visiting.
What temperature is Alkali Lake Hot Springs?
Alkali Lake Hot Springs has a reported soak temperature of 115°F and a historical source temperature of 135°F in survey records. Historical data may not reflect current conditions — always test water before entering.
Is Alkali Lake Hot Springs clothing optional?
Alkali Lake Hot Springs is listed as traditionally clothing-optional in directory records. Confirm current rules before visiting, as policies change.
How do you access Alkali Lake Hot Springs?
Alkali Lake Hot Springs is on public land — verify current road access, fees and rules with the land manager before visiting.
Where to stay in Mammoth Lakes
Choose town lodging for the Long Valley springs reached from US-395 and Benton Crossing Road. The pools are outside town on separate access roads.
Mammoth Lakes is about 11 mi from the spring (straight line).
We may earn a commission from bookings through these links, at no extra cost to you.
Sources & references
- Hot Springs Locator — Alkali Lake Hot Springs (135F source, pipe-fed tub, 'does not provide the best soaking') — community · 2023
- HotWaterSlaughter — Alkali Lake Hot Spring (culvert source ~120F; PVC plugged & pool dry, 2007) — community · 2020
- Hotspringers — Hilltop/Long Valley area field report (June 2024; gate sometimes closed) — community · 2024-06
- Hot Springs Guides — Hilltop/Pulky's (BLM Bishop FO, valve-adjusted tub) — community · 2025
Additional references for this record; a source link does not guarantee current conditions.
Details above were verified against the named sources on their listed dates — conditions change, so recheck before traveling. · How we verify our data · Report a correction
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