January 21: First known U.S. case of COVID-19 reported in Snohomish County by Centers for Disease Control
February 26: First known U.S. death from COVID-19 occurs in Kirkland, part of an outbreak at a nursing home.
February 29: COVID-19 pandemic in Washington (state) officially begins when the first cases of COVID-19 in the United States are reported, and a state of emergency is declared by Governor Inslee