There are truly so many different variations of these large letter postcards. I'm not sure of the date of this one but it was published by E.C. Knopp who sold the company in 1956. I'm also not sure what to make of these axe wielding men and their headgear and no lumberjack shirts, but taking a cue from them this looks like an early 1950's design. Also, the Grand Coulee Dam and the Floating Bridge were both built before 1942.
the State Capital building in Olympia
the Grand Coulee Dam
locks in Seattle
totem pole in Pioneer Park, Seattle
the state flower (rhododendron)
Olympia National Park
Floating Bridge on Lake Washington
Washington State seems to like Floating bridges as they have three of them over Lake Washington alone. I believe this one is the Lacey V Murrow Memorial Bridge (official name), built in 1940. It sank in 1990, but was rebuilt and now carries eastbound traffic with a newer floating bridge running parallel (built 1989) for the westbound traffic.
The totem pole has an interesting history. Originally in a Tlingit village in Alaska, a group of businessmen touring Alaskan ports stole it in 1899 and took it back to Seattle where it was erected in Pioneer Place Park. Apparently, everyone in the village had been out fishing when these "prominent Seattle citizens" chopped down the pole. When an arsonist destroyed the 60' pole in 1938, the city (with some cheek) sent the pieces back to the Tlingit tribe who carved a new one and gave it to Seattle (after finally getting paid for the one that was originally stolen)