Fort Clatsop National Memorial was established in 1958 to commemorate the culmination and 1805-06 winter encampment of the Lewis and Clark Expedition. The 125 acre park is located within the Columbia River estuary on the northwest coast of Oregon. The topography of the park varies in elevation from sea level mudflats on the Lewis and Clark River to 70 feet on the forested slopes of Clatsop Ridge, a western extension of the Coast Range. The park’s maritime climate is characterized by relatively warm, dry conditions in summer and fall and mild, wet conditions in winter and spring. Mean annual precipitation averages 74 inches in the coastal lowlands, mostly as rain. The coastal geology is composed of Quaternary marine and non-marine terrace deposits and alluvium in the lowlands with Miocene and marine sandstone, siltstone, and shale in the uplands.
Ecosystems within the park vary from estuarine mudflats and tidal marshes to shrub wetlands, forested swamps, and coastal temperate rainforest dominated by Sitka spruce as large as six feet in diameter. Wetlands comprise approximately half the park's acreage and include the tidally influenced Lewis and Clark River, low-gradient brackish sloughs, freshwater ponds, and several small freshwater streams and springs. These wetlands provide valuable habitat for a number of threatened and sensitive fish, amphibian, bat and bird species. Bald eagles nest in the area and can often be seen in flight or perching along the river. Fort Clatsop is within the coastal Sitka spruce vegetation zone, dominated by Sitka spruce and western hemlock, with a diversity of understory shrubs, ferns and wildflowers. Approximately half of the Memorial is forested, with a number of trees over 100 years in age. The park's forests provide high quality habitat for pileated woodpeckers, owls, and sensitive bat and vole species. A resident herd of Roosevelt elk frequents the park's forests and shrub wetlands.
Flora and fauna diversity within the Memorial are high relative to the park's size, reflecting its habitat diversity, its moderate climate, its location along the Pacific flyway and its proximity to the Pacific Ocean. The park is home to more than 135 vertebrate species, including at least 43 mammals, 74 birds,10 amphibians, 2 reptiles and 9 fish. Two-hundred fifty species of vascular plants and 74 species of bryophytes have been documented in recent surveys and are represented in the park herbarium. Many additional species of invertebrates, fungi and lichens have yet to be inventoried.
The park's natural resources are significant from a historic as well as a contemporary perspective. During the winter of 1805 - 06, explorer Meriwether Lewis described, sketched or collected more than 30 of the region's plant species, including evergreen huckleberry (Vaccinium ovatum) and salal (Gaultheria shallon), both new to science. Lewis's journal entries also documented 23 mammals, 28 birds and a number of fish, reptile, amphibian and invertebrate species during the expedition's stay at Fort Clatsop.
To learn more about Fort Clatsop National Memorial please visit the park's website at www.nps.gov/focl.
