Mawson Bridge is an abandoned bridge over Butte Slough has seen better days since it was built in 1941. This old Pratt through truss designed bridge used to be called the Old Butte Slough Bridge. There is a section of the bridge remaining, and there are several piles (Concrete that holds the bridge up) still marking the former route of Pass road to highway 20. There is a new bridge to the north replacing the old bridge, and has a large parking area for anglers, and summertime swimmers. Very picturesque area with a great view of the Sutter Buttes.