The bridge was added to the National Register of Historical Places in 1992.
(Structure #92000290)
Historic Significance: Architecture/Engineering
Architect, builder, or engineer: O.S. Batten/Works Progress Administration
Historic Function: Transportation
The bridge has been closed to motorized vehicles but since undergoing extensive renovations in August 2006, is open to bicycle and foot traffic.
You are looking for a small container with room for a few trade items hidden near the bridge.
For good measure, (BYOP). 
