The Oregon City Bridge, also known as the Arch Bridge, is a steel through arch bridge spanning the Willamette River between Oregon City and West Linn, Oregon, United States. Completed in 1922, it is listed on the National Register of Historic Places. It was built and is owned by the Oregon Department of Transportation (ODOT) as part of Oregon Route 43 and is the thirdsouthernmost Willamette bridge in the Portland metropolitan area, after the Boone Bridge in Wilsonville and the Oregon 219 bridge near Newberg. The bridge is 745 ft (227 m) in length and 28 ft (8½ m) wide with a 360 ft (110 m) long main span that provides 49 ft (15 m) of vertical clearance at low river levels. The narrow width causes problems for large vehicles that cross it, often requiring traffic going in the other direction to stop. TriMet buses ceased using the bridge in 2009. This bridge is the only Oregon bridge to be encased in gunite, which protects it from corrosive sulfur dioxide emissions from paper mills south of the bridge. The concrete look was favored by bridge designer Conde McCullough, designer of 500 Oregon bridges. His signature detailing is evident in the obelisk pylons with sconced light fixtures, ornate railings, and Art Deco piers. The Oregon City Bridge is just downstream from the tall Willamette Falls and the Willamette Falls Locks, the oldest navigational locks in the United States. Downstream from this bridge is the George Abernethy Bridge, which carries Interstate 205. History The bridge was built to replace a pedestrian cablesuspension bridge completed in 1888. This existing bridge was utilized continuously during the construction process of the replacement, not only as access to the site for men and materialsassembling the box steel frames and pouring the reinforced concrete from its walkwaybut also as the main support system during the completion of the arch itself. Construction was made difficult by the engineering challenges posed by the great depth of the river at the site and worse from the need to manage and accommodate the frequent and ever increasing water traffic on its surface. The completed bridge was opened to the public on December 28, 1922, with the cost of construction reported as $300,000. The piers were designed to accommodate public restrooms. The deck widens at the piers to provide room for the stairways – one on each side of the deck –