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Crowberry Bog



Crowberry Bog is located above the Hoh River on the western Olympic peninsula. This site is the only documented raised bog in the western, contiguous United States and the southernmost in western North America.  The highest point of the bog is approximately 9 feet higher than the lowest point of its outer margin. Furthermore, it appears to be a rare type of raised bog called a plateau bog, which is only found in areas with a strong oceanic climate such as northeastern North America and the Baltic region of Europe. Three globally rare plant communities, the globally rare Makah Copper butterfly (Lycaena mariposa ssp. charlottensis), and two state rare mosses (Sphagnum austinii and Splachnum ampullaceum) are found at the bog. Because of these important features, the Washington Department of Natural Resources, Natural Heritage Program (DNR-Natural Heritage) is pursuing designation of this site as a state Natural Area Preserve. Natural Area Preserves are managed by the Washington Department of Natural Resources, Natural Areas Program to protect the best remaining examples of ecological communities and rare plant and animal species.


Exemplary Ecosystem Services

Aesthetic/Cultural Heritage Value/Provisioning


Conservation Status and Threats

  • Conservation status

    State Protection
  • Adjacent land use

    Upland Forest/Woodland
  • Approximate natural buffer width

    > 100 ft
  • Other Information



  • Approximate size (ha):

    Approximately 12 hectares
  • General wetland characterization:

    Crowberry exhibits characteristics of a plateau bog, a type of raised bog limited to areas with a strong maritime influence. 
  • Wetland type: Raised bog.
  • Adjacent water bod(ies)

  • Approximate stream order

  • Name of body of water

    Hoh River
  • Surficial geology

    Crowberry Bog occurs on glacial drift derived from alpine glaciers of Fraser age. These drift deposits occur on a plateau above surrounding deposits of glacial outwash and alluvial deposits associated with the Hoh River. The Olympic Mountains were covered by a solid ice cap during Quarternary glaciation (Heusser 1974). Alpine glaciers, derived from this ice cap, flowed down the major river valleys. More than 47,000 years ago, the Hoh river valley was glaciated to its present day mouth. About 19,000 years ago the retreating ice terminus stagnated in the general area in which Crowberry Bog occurs (Heusser 1974). Ice blocks left in this area did not melt for another 3 to 4, 000 years at which point wetland development was initiated (Heusser 1974), ultimately leading to the development of the raised bogs that are present today. A landform resembling a morainal deposit occurs along the eastern edge of Crowberry Bog.


    Heusser, C.J. 1974. Quaternary Vegetation, Climate, and Glaciation of the Hoh River Valley, Washington. Geological Society of America Bulletin v.85, pp. 1547-1560.

  • Soils

    Soils in Crowberry Bog are mapped as Orcas peat deposits which are derived from Sphagnum species (USDA 1975). A peat core from Crowberry Bog indicated that Sphagnum-derived peat extends to a depth of 12.5 feet (3.8 meters; Heusser 1974). Below the Sphagnum peat is a layer of muck extending another three feet (1 meter) in depth followed by a mix of muck and clay which extends to the bottom of the wetland basin at a depth of 19 feet (5.8 meters; Heusser 1974). Soils around the bog and on top of the glacial drift are mapped as the Lagitos-Klone-Tealwhit soil complex which consists of clayey or fine-texture old alluvium (USDA 1975; DNR 2014). This complex consists of poorly drained, somewhat poorly drained silty loam over sand and gravel, and well-drained gravelly loam derived from glacial outwash (DNR 2014).


    DNR 2014. Soils GIS layer derived from the Private Forest Land Grading system (PFLG) and subsequent soil surveys. Washington Department of Natural Resources, Olympia, WA.

    Heusser, C.J. 1974. Quaternary Vegetation, Climate, and Glaciation of the Hoh River Valley, Washington. Geological Society of America Bulletin v.85, pp. 1547-1560.

    USDA 1975. Soil Survey of Jefferson County Area, Washington. U.S. Department of Agriculture, Soil Conservation Service in cooperation with the Washington Agricultural Experiment Station.


Flora and Fauna

  • Dominant flora

    Bog laurel (Kalmia microphylla), Labrador tea (Ledum groenlandicum), crowberry (Empetrum nigrum), cranberry (Vaccinium oxycoccos), roundleaf sundew (Drosera rotundifolia), cottongrass (Eriophorum chamissonis), white-beakred rush (Rhynchospora alba), western hemlock (Tsuga heterophylla), shore pine (Pinus contortra var. contorta), beargrass (Xerophyllum tenax), skunkcabbage (Lysichiton americanus), rusty peat moss (Sphagnum fuscum), and red peat moss (Sphagnum rubellum)
  • Unique flora

    A couple of rare species: state rare mosses (Sphagnum austinii and Splachnum ampullaceum), state rare plant (Carex stylosa). The presence of beargrass in the bog is unusual.
  • Dominant fauna

    Roosevelt elk and black bear frequent the site.
  • Rare fauna

    Globally rare Makah Copper butterfly (Lycaena mariposa ssp. charlottensis)


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