The online encyclopedia of Washington State history offers a number of essays on topics related to the Ship Canal, including Lake Washington Ship Canal, Montlake Cut, and Union Bay Natural Area, among many others. Browse all essays and slide shows at HistoryLink.org.
The Seattle Municipal Archives shares photos of sawmills on Salmon Bay in this interactive virtual exhibit: http://clerk.seattle.gov/~F_archives/maps/sawmills/sawmills.html
In addition, King County Archives and Seattle Municipal Archives jointly present an online exhibit: The Lake Washington Ship Canal and the Mills of Salmon Bay. This is an expanded version of the exhibit installed in the King County Courthouse pedestrian tunnel.