Cartoon map of the Washington landscape in the 1930s.
An interactive view of the map that explains some of the images as well as links to the source is found at www.vox.com/washington-state-annotated-map.
A couple notes on a few of the images. The Oregon Trail is shown passing through the Blue Mountains in southeast Washington. The trail crossed the Blues in Oregon.
The image of the two Indians chasing the troops is likely a reference to the united tribal effort against Colonel Steptoe. Not a fair portrayal as the Indians had guns and by accounts I have read actually had better guns.