Early Kroll Map Co. manuscript map of a Washington-based seaplane company.
The map shows routes around Puget Sound and British Columbia. The routes are Olympia-Tacoma, Tacoma-Seattle (Seaplane Base Lake Union), Seattle-Vancouver, Seattle-Victoria, Victoria-Vancouver, and Vancouver-Nanaimo.
Lake Union was home of the first International air mail route in the United States, starting flights in 1919.
Fort Lawton, Fort Flagler, Fort Worden, and Fort Casey are shown on the map. Fort Flagler was an active United States Army Base from 1897 to 1953. Fort Worden was an active United States Army base from 1902 to 1953.
The compass rose includes the acronym "AWA" presumably for the airline that operated these routes. We have been unable to trace any such airline operating in the Seattle area in this timeframe.