Isthmus Slough Bridge, Spanning Isthmus Slough at Milepoint 0.2, Coos City to Sumner Road, Coos Bay, Coos County, OR

Significance: The Isthmus Slough Bridge is significant as a good example of the bascule bridge type. This bridge is unique within the Oregon context at it is the only known bascule structure that utilizes a block and tackle lifting mechanism, as opposed to the more common motorized lifting mechanism. The lack of motorized technology distinguishes this structure within Oregon's context of moveable bridges. The Isthmus Slough Bridge is also significant as a late example of the bascule type within Oregon, as it is only one of three bascule spans built after WWII.
Survey number: HAER OR-144
Building/structure dates: 1955 Initial Construction