The geology of the entire state of Washington has been mapped at 1:100,000 scale, and is available both as published maps of 30- by 60-minute quadrangles and as statewide digital GIS data.
Published 1:100,000-scale Geologic Maps
Standard 1:100,000-scale geologic maps can be accessed through the PDF above. Maps with the prefix "DGER" were published by the Division of Geology and Earth Resources. Publications with the prefix "USGS" were published by the U.S. Geological Survey. Maps, including quadrant and whole-state maps, are listed by geographic location (on the map), and by map and author name (page down on the PDF). 7.5-minute quadrangles are listed separately. (Click on the inset map in the lower right corner of the PDF.)
All of these maps may be consulted at the Washington Geology Library in Olympia. They may also be available at a nearby university library. The quadrant and whole state maps can be purchased through the Washington State Department of Printing. See p. 3 of the Publication List.
Statewide Digital GIS Data
ESRI shapefiles of the 1:100,000-scale geology of the entire state are available online: