How many tectonic plates interact under Washington?

Washington state is primarily influenced by three major tectonic plates: the Juan de Fuca Plate, the North American Plate, and the Pacific Plate. The Juan de Fuca Plate subducts beneath the North American Plate along the Cascadia subduction zone, while the Pacific Plate interacts with the North American Plate along the San Andreas Fault system. These interactions contribute to the region's seismic activity and volcanic features.