The Washburn Tunnel, spanning the Houston Ship Channel of Buffalo Bayou, is a subaqueous trench-type tunnel structure connecting the Houston suburbs of Galena Park and Pasadena in Harris County, Texas. The two-lane motor vehicle tunnel is constructed of two steel tubes, with one fitted inside the other. Concrete fills the 18-inch void between the tubes, and a layer of concrete, two feet thick, covers the outer shell. The brick roadway is now paved, and the tunnel interior is covered in its original white ceramic tiles. A 3-story control building of steel frame construction straddles the tunnel`s north entrance and is clad with granite and cast stone panels as well as vertical siding of zinc. A traffic roundabout and a traffic circle leading to the tunnel roadways from the north and south, respectively, are also included in this nomination. While some changes have been made to the tunnel and control building structure since its construction.