Smith Island is located in Snohomish County, just east of Everett, in Washington State. The island is within the Snohomish River delta that flows out into Possession Sound. Smith Island was logged, farmed, and homesteaded in the early 20th Century. Dikes were erected to protect the farmland from saltwater during high tide. Smith Island is separated from the mainland.
Smith Island is within the Snohomish River estuary near Everett. The site is bounded by Union Slough and Spencer Island to the east and north, Interstate 5 to the west, and Everett’s wastewater treatment plant to the south.