Colonial Building Co.

of Spokane, Washington
Hamma Hamma River Bridge North (Mason County, Washington)
Contractor, 1924
Rainbow arch bridge over Hamma Hamma River on US 101
Open to traffic

Hamma Hamma River Bridge South (Mason County, Washington)
Built 1924
Rainbow arch bridge over Hamma Hamma River on US 101
Open to traffic

Indian Timothy Memorial Bridge (Asotin County, Washington)
Contractor, 1923
Bypassed two-span through arch bridge over Alpowa Creek on US 12
Open to pedestrians only

Seufert Viaduct (Wasco County, Oregon)
Contractor, 1920
Stringer bridge over Fifteen Mile Creek on Viewpoint Road (Historical Columbia River Highway) in The Dalles
Open to traffic