Ecoregions of Washington State
In Washington state alone there are 13 ecological regions.
- Outer Olympic Peninsula--west side of the Olympic Peninsula facing the Pacific Ocean
- Inner Olympic Peninsula--east side of the Olympic Peninsula on the 'rain shadow' side of the Peninsula's mountains and hills
- Puget Sound--flat,low valley of the Puget Sound formed by the weight and scouring of glaciers during the last ice ages
- Willamette Valley--northernmost extent of the Willamette Trough that has its major portion in Oregon; includes only the lowlands around Vancouver, Washington
- Southwest Cascades--southwest Cascades from Snoqualmie Pass to the Columbia River but not including the Willlamette Valley
- Southeast Cascades--southeast Cascades from around American Ridge south to the Columbia River
- East Central Cascades--north to Lake Chelan and south to around American Ridge
- Northwest Cascades--south to Snoqualmie Pass
- Northeast Cascades--south to Lake Chelan
- Columbia Basin--steppe vegetation up to the lower timberline, but excluding the Blue Mountain Steppe zone to the north and east of the Blue Mountains
- Blue Mountains--Blue Mountains, including the Blue Mountain Steppe to the north and east of the forested Blue Mountain zones
- Okanogan Highlands--from the eastern foothills of the Okanogan valley to the crest of the Kettle Range; south to the Columbia Basin
- Northeast Corner--northeastern Washington; west to the Kettle Range; south to around Cheney
These ecoregions are distinguished by different soils, native vegetation, topography, and land use.