Southern end of the Moses Coulee

In 1919, the Sunset Highway was rerouted over Blewett Pass and bypassed Ellensburg. The old route From Ellensburg to Wenatchee through Quincy then became the Southern Division of the Sunset Highway.

In 1926, a new highway was completed between Wenatchee and Quincy. This new road eliminated the Moses Coulee Ferry crossing. The Southern Division of the Sunset Highway was then known as the Wenatchee-Quincy Highway and was paved in 1926. In 1937, this road became Primary State Highway 10 and the new North Central Highway between Quincy and Davenport became Primary State Highway 7.