The State Data Center (SDC) program is a cooperative program between the states and the Census Bureau created in 1978 to make data available locally to the public through a network of state agencies, universities, libraries, and regional and local governments. The Business and Industry Data Center (BIDC) program was added in 1988 to meet the needs of local business communities for economic data. The Office of Financial Management is the state agency responsible for administering these programs in Washington state.

Small Area Estimates Program (SAEP) estimates are meant to provide a consistent set of small area population and housing data for statewide applications. SAEP estimates are generated for census areas and other areas of statewide significance.

Population density is the average number of people per unit of land area. In the U.S., the most common unit of population density is persons per square mile. The land area measurement excludes lakes and other water areas within.

Population change

In accordance with RCW 43.62.035, the Office of Financial Management shall determine the percentage increase in population for each county over the preceding ten-year period, as of April 1.

Click on a tab below to access geographic data. Some of the data files are large and may require additional time to download.