Blueprint and diazo copies of plans for projects in Oregon and Washington, including the Willamette Falls locks; modifications to a dam and lock on the Yamhill River; gun emplacements at Fort Stevens; and a Spokane, Portland and Seattle Railway station and water tower. The U.S. Army Corps of Engineers is a hybrid military-civilian organization that has played a role in developing Oregon's water infrastructure since the 1860s, and which established an office in Portland, Oregon, in 1871.