The first confirmed case relating to the COVID-19 pandemic in the United States was announced by the state of Washington on January 21, 2020. Washington made the first announcement of a death from the disease in the U.S. on February 29 and later announced that two deaths there on February 26 were also due to COVID-19.Washington had 98,201 confirmed cases and a total of 2,239 confirmed deaths as of October 18, 2020. Public health experts agree that the true number of cases in the state is much greater than the numbers that have been confirmed by laboratory tests. Governor Jay Inslee issued a statewide stay-at-home order on March 23 to last at least two week.

On March 4, officials reported the tenth death in the U.S. attributable to coronavirus.King County Public Health Department reported 10 new cases, including one death.On March 5, the Washington State Department of Health reported 31 new cases with the first new case reported outside of Snohomish and King counties. County case totals were Snohomish County 18, including 1 death; King County 51, including 9 deaths.

Seattle mayor Jenny Durkan declared a civil emergency on March 3. On March 3, Public Health – Seattle & King County began establishing the White Center COVID-19 quarantine site. On March 5, United States Vice President Mike Pence visited the state governor at Washington State Emergency Operations Center on Camp Murray, north of the state capital Olympia, to discuss the crisis. On March 12, Governor Inslee announced closures for all public and private K-12 schools in King, Snohomish, and Pierce Counties beginning from March 17 through at least April 24.Later, on March 13, Inslee announced K-12 closures until at least April 24 throughout the state.

Several national media outlets reported that fewer Seattle residents were observed outside in public places in early March. Local businesses, especially in tourist areas, reported fewer customers and sales. On March 10, Seattle-based Alaska Airlines announced the company was preparing to cut its flight schedule and freeze hiring due to the sharp drop in airline bookings because of the pandemic. On March 12, the city of Seattle announced that the public library system, community centers, and other recreation facilities would be closed until at least April 13. 

Westfield closed all its malls – including Westfield Southcenter, the largest shopping mall in Washington state and the Pacific Northwest – on March 19. Bellevue Square and Lincoln Square had closed the day before. Boeing announced on March 23–24 that all manufacturing facilities in the Puget Sound area and the Grant County International Airport 737 Max storage and testing facility in Moses Lake would be closed for two weeks, starting March 25. Retail closures not subject to the March 23 stay-at-home edict included retail pharmaceutical providers and retail cannabis and alcohol providers, considered an essential need by the order.On March 4, Northshore School District became the first school district in the state to announce an extended district-wide closure due to the pandemic, shifting to remote online learning. The closure was initially scheduled to last up to 14 days.

The two largest state universities, University of Washington (UW) and Washington State University (WSU) curtailed on-campus classes during the pandemic. UW announced its closure on March 6; and on March 11, WSU announced the closure would begin after its spring break, on March 23.On March 11, school districts in the Greater Seattle area, including Seattle Public Schools, Lake Washington School District, and Bellevue School District, announced their closures shortly after Governor Jay Inslee‘s social distancing proclamation .

Many school districts in Snohomish County also announced closures that would start in the next few days, including Snohomish School District, Monroe School District,Marysville School District, Everett School District and District. On March 12, the governor invoked his emergency power and mandated the closure of all private and public schools in King, Pierce and Snohomish Counties, from March .On April 6, it was announced that all Washington State K-12 schools would be closed through the end of the school year.In July, Washington State University announced that the fall 2020 semester would offer full remote classes.