Photo by Magic K on Pexels
🇺🇸 USA · King County, Washington
♨ Temperature
48°C
⛰ Altitude
900 m
⚗ pH
7.4
💧 TDS
780 mg/L
🌊 Flow rate
8 L/s
📅 Established
Known since late 19th century; managed by Northwest Wilderness Programs since 1976
✓ Verified on 2026-07-22
Goldmyer Hot Springs sits deep in the Middle Fork Snoqualmie River wilderness in King County, Washington, accessible only by an 8-mile trail through one of the most intact old-growth forest corridors remaining in the western Cascades. The springs emerge from the base of a basalt cliff at up to 53°C, feeding a sequence of natural pools including a distinctive cave pool where hot water flows through a shallow cavern in the rock. The site is managed by Northwest Wilderness Programs, a non-profit that limits daily access to a maximum of 20 people to protect both the fragile thermal ecosystem and the old-growth forest approach. Advance reservations are required, and the drive and hike require significant commitment. The cave and pools are lined with thermophilic algae and microbial mats in vivid orange, yellow, and green — communities of organisms adapted to thrive only in the high-temperature mineral water. The Snoqualmie watershed is one of the most ecologically significant old-growth remaining in the central Cascades, and Goldmyer is one of the few thermal sites anywhere in North America that has been managed explicitly for small-scale access preservation for nearly 50 years.
| Sulphur (H₂S) | 1.4 mg/L |
| Sodium | 92 mg/L |
| Bicarbonate | 288 mg/L |
| Silica | 44 mg/L |
| Calcium | 38 mg/L |
| Magnesium | 12 mg/L |
The Middle Fork Snoqualmie valley is within the traditional territory of the Snoqualmie Tribe, whose name is carried by both the river and the valley. The Snoqualmie people have inhabited this watershed since time immemorial and continue to exercise treaty rights in the region. 'Snoqualmie' in the Snoqualmie language refers to the Moon — the tribe's origin story connects them deeply to this mountain landscape.
Goldmyer was managed as a private mineral spring claim in the late 19th century and fell into informal use during the mid-20th century. Northwest Wilderness Programs took over formal management in 1976 in one of the earliest examples of a community non-profit managing a backcountry hot spring for long-term conservation rather than commercial development. The 20-person-per-day cap has remained in place for nearly 50 years, making Goldmyer one of the most carefully protected hot springs in the United States.
The 20-person daily limit is strictly enforced and requires advance reservation. The springs themselves are part of an ecologically significant riparian corridor within the Okanogan-Wenatchee National Forest, and the thermophilic microbial mats in the cave and pools represent scientifically important extremophile communities. Vehicle access ends miles from the site, reducing impact further.
Phone+1 206-789-5631
Websitewww.goldmyer.org
AddressMiddle Fork Snoqualmie River Road, King County, WA 98065, USA