Poison Lake
Poison Lake reaches 122 degrees Fahrenheit in north-central Washington's Okanogan County, creating a thermal difference of 70.7 degrees above the ambient air temperature. The spring sits 305 meters from Golden Road near Oroville, requiring a short walk to access this exceptionally hot feature in Washington's rain shadow interior.
The spring occupies Okanogan County's transitional landscape where the wet Cascade forests give way to the semi-arid interior. At this elevation, the terrain receives 22.1 inches of annual precipitation and 56.5 inches of snow, supporting vegetation adapted to the rain shadow climate. Average annual air temperatures of 51.3 degrees reflect the continental influence, with summers warmer and winters colder than the maritime west. The area's topography shows the characteristic rolling hills and valleys of the Okanogan Highlands, with mixed conifer forests giving way to open ponderosa pine and grassland as precipitation decreases eastward.
The name 'Poison Lake' suggests either toxic mineral content, alkaline water chemistry, or a cautionary designation from early settlers or Indigenous peoples. No documented development history appears in the available records, indicating the spring likely remains in a relatively natural state without commercial infrastructure or formal recreational development.
Visit during late spring through early fall when the short walk from Golden Road remains accessible. Winter snow accumulation of 56.5 inches may make the approach difficult from November through March. The 122-degree source water requires careful handling and likely needs mixing with cooler water for safe bathing. Lost Lake Group Unit campground 30 kilometers away provides the nearest reservable camping option, though the distance makes it more practical as a base for exploring multiple thermal features in the region.
Is Poison Lake worth visiting?
Best for
- Hot spring soaking
- Overnight camping trips
Overview Lost Lake Group Site is located in Lost Lake Campground which is situated on the northern edge of Lost Lake on the Tonasket Ranger District of the Okanogan-Wenatchee National Forest. Set beneath mixed-conifer forest and surrounded by mountains, this campground offers one group site, suitable for large family and group camping excursions as well as several non-reservable single and double sites.Recreation Lost Lake Campground offers outdoor enthusiasts the opportunity to hike, fis...