Snohomish County is located on Puget Sound, between Skagit County to the north and King County (and Seattle) to the south. Covering 2,090 square miles, it is by area the 13th largest county in Washington. Snohomish County's varied topography ranges from saltwater beaches, rolling hills and rich river bottom farmlands in the west to dense forest and alpine wilderness in the mountainous east. Glacier Peak, at 10,541 feet, is one of the highest mountains in the country.

Snohomish is one of the fastest growing counties in the state. The current population is 628,000 (April 2002), reflecting a 30% growth rate since 1990. Most of the population is concentrated in the lowland western third of the county, with slightly more than half of the residents living in incorporated cities (327,540). Everett, pop. 95,990 (Census 2000), is the largest city and has served as the county seat since 1897.

The diversity of Snohomish County's population is typical of the Puget Sound area, with about 85.6 of the county's residents identifying themselves as white, 0.3% as Pacific Islander, 1.4% as American Indian, 1.7% as black, 3.7% as multiracial, and 4.7% as Hispanic (Census 2000 figures). Snohomish County's work force ranges from farm and forest workers to those employed in the forefront of modern manufacturing and technological industries. As of 2001, about 11% of non-agricultural workers in Snohomish County were employed by Boeing.

Snohomish County enjoys a moderate year-round climate, with average temperatures ranging from about 75 degrees Fahrenheit in July to about 33 degrees in January. The Olympic Mountains to the west, across Puget Sound, shelter the area from excessive precipitation coming off the Pacific Ocean. Annual precipitation in the western part of the county is 35 inches, but increases sharply as the elevation climbs into the Cascades Mountains (Town of Index, 110"-120").

In 1853, the federal government divided the Oregon Territory and created Washington Territory, itself divided into eight original counties: Island, Pierce, King, Jefferson, Thurston, Clark, Pacific and Lewis. The population of the new territory was 3,965 settlers and an estimated 20,000 Native Americans. The immigrant settlers of Washington Territory continued to push north along Puget Sound, encouraged by the discovery of gold fields along the Fraser River (in what is now British Columbia), coal at Bellingham, and a fast-developing timber industry.

1861—As communities began to develop in what was later to become Snohomish County, better local representation and control were demanded. With an immigrant population of only 44, and a Native American population of about 1,500, Snohomish County was created on January 14, 1861.

1889—On November 11, 1889, Washington was admitted to the United States, becoming the 42nd state. The new state constitution provided for a three-commissioner form of government for counties, with each commissioner elected to represent a district of equal population. There was no separation of powers—the county commissioners served in administrative, legislative, and quasi-judicial roles.

1948—In 1948, the 21st amendment to the state constitution was approved, providing a means for counties to adopt a different form of government called "home rule." Residents of Snohomish County first attempted to adopt a home rule county charter in 1968, but the change was not approved by the voters until eleven years later. The new, reorganized charter form of government became effective May 1, 1980.

1980—Snohomish County government has operated under a county charter since 1980. In the mid-1990's, residents in the northern part of the county mounted a movement to split off part of the county and form a new county. The movement failed for lack of widespread support.