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 Geologic Maps
In the above index, publications with the prefix "DGER" are available from the Washington Division of Geology and Earth Resources; those with the prefix "USGS" are available from the U.S. Geological Survey.
All of these maps may be consulted at the Washington Geology Library.
Statewide Digital GIS Data
ESRI shapefiles of the 1:100,000-scale geology of the entire state are available online: