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About King County's environment

King County's environment

This page provides an introduction to the characteristics and physical features of King County including its biological environment. To find environmental services, please see Environmental services in King County, Washington.


Mount Rainier above West Marginal Way, 2011King County covers 2,131 square miles is bounded by Puget Sound to the west and the Cascade Range to the east.  The region has been scoured by ice-age glaciers that carved Puget Sound, Lake Washington and Lake Sammamish and shaped our lowland hills, leaving behind patches of conglomerate till and gravelly outwash soil.   Except for rural Vashon Island in central Puget Sound, the western county is covered by cities while the development pattern becomes gradually sparser to the east, with suburban developments, then rural residential lands, then farms and forestlands. The eastern half of King County is mountainous, and mostly set aside as wilderness areas, forestlands or restricted watersheds that capture and store the region's drinking water.

King County watersheds map

Across King County, residents live among trees and look up to the Cascade Mountains in the east, Mount Rainier to the south and the Olympic Mountains to the west, with marvelous views of Puget Sound and the region's many lakes.


King County precipitation map - rainfall, snow and other precipKing County enjoys a mild Pacific maritime climate, which means its weather is heavily influenced by atmospheric conditions over the Pacific Ocean.  About  two-thirds of the Pacific Northwest precipitation occurs during half of the year from October through March, due to the Pacific storm track , and much of this precipitation is captured in the mountains. Precipitation declines from late spring to early fall with high pressure systems to the west, generally keeping the region fairly dry with pleasant summertime temperatures. On average, King County gets about 46 inches of  precipitation every year.

As the climate continues changing in King County, we expect more rain and probably more flooding from extreme precipitation events, less snowpack in the mountains lasting into summer, rising sea level along the Puget Sound shoreline and more severe droughts during summer.

Animals and plants

Chinook salmon A diverse and interconnected web of animals and plants call King County home, with marine animals having staked the claim as the region's icons including the salmon and orca whale, otter and the seahawk.  Among the county's land animals, mollusks also enjoy iconic status — at least the region's slugs are well-known — and among plants, the majestic Douglas fir and western red cedar are firmly planted in the region's identity.  Besides  Puget Sound's rich sea life, our famous slugs and timber trees, the region's forests teem with life such as deer, bear, coyote, fox, bobcat, eagles, various owls and other birds, hundreds of native plants, lichens and myriad other living things all along the food chain.


  • More than 8,000 infestations of Class A and B noxious weeds are controlled in the County each year (2011)
  • In the last five years, more than 76,600 lineal feet of riparian buffer and 2,900 lineal feet of marine shoreline have been restored (2010).

Water resources


  • 760 lakes and reservoirs
  • 975 wetlands
  • 38.15 inches average annual participation
  • 6 major river systems
  • 3,000 miles of streams
  • 100 miles of marine coastline

Farms and forests

Statistics (2010)

  • 850,000 acres of forestlands
  • Number of farms: 1,800;
  • Acres of farmland in production: 50,000;
  • Number of farmers markets in King County: 41;
  • Acres of farmland preserved through the Farmland Preservation Program: 13,200;

Enjoyment and appreciation

The logos that identify most cities in King County incorporate images of water, mountains, trees and/or wildlife. Our environment is very much a part of the region's identity.

In King County, environmentally-precious lands such as waterfront properties, land with water views or mountain views, and lands near parks and trails are generally more valuable owing to intense competition in our market economy.  Yet, King County offers hundreds of parks, trails and natural lands owned by the public and open for the enjoyment of all residents, rich and poor alike.

In 2012, King County celebrated the 30th Anniversary of Conservation Futures, a forward-thinking tax program that King County voters approved decades ago to protect and set aside the best places from development including parks, trails, forests and farms.  An anniversary video describes the historical importance of our citizen-supported tax program:

King County environment - infographic
Infographic: King County's environment