Jefferson County

Location of Jefferson County in Washington StateJefferson County is located in the northern portion of Washington State’s Olympic Peninsula.  It is bordered on the west by the Pacific Ocean, the north by Clallam County, the northeast by the Strait of Juan de Fuca, the east by the waters of the Hood Canal and Admiralty Inlet, the southwest by Grays Harbor County and the southeast by Mason County.   As of the 2010 U.S. Census, Jefferson County had total land area of 1,803.70 square miles and a population of 29,872.  Port Townsend is its largest city with a population of 9,113.  Also of interest:

  • The intersecting watershed sub-basins(7): Hoh-Quillayute, Queets-Quinalt, Lower Chehalis, Dungeness-Elwha, Hood Canal, Puget Sound and Skokomish.
  • Major lake:  Leland Lake
  • Major rivers:  Hoh River, Queets River, Clearwater River, Dukabush River, Dosewallips River, Little Quilcene River, Quinault River and Solleks River.
  • Mount Olympus (7,980 feet) is highest peak in the Olympic Mountains and the central feature of the Olympic National Park.

U.S. Census Bureau QuickFacts for Jefferson County, WA

Office of Financial Management (OFM) county data for Jefferson County, WA


Rhinoceros Auklet carrying sand lance. Photo by Peter Hodum.

Paper: A model approach for estimating colony size, trends and habitat associations of burrow-nesting seabirds

A paper in the May 2013 issue of The Condor [115(2):356–365, 2013] describes a repeatable and statistically robust approach to monitoring burrow nesting seabirds in the Salish Sea and the California Current that can be applied at single- or multi-island scales. The approach can be applied to both relatively common and important members of the seabird community like the Rhinoceros Auklet and to species of conservation concern like the Tufted Puffin.

Protection Island. Image courtesy of NOAA.

Protection Island

Protection Island, a National Wildlife Refuge in the Strait of Juan de Fuca, provides important habitat for seabirds and marine mammals.


2010 Census Quick Facts for Jefferson County, WA

Learn more about demographics in Jefferson County, Washington.  The U.S. Census Bureau published the following quick facts.