Big Thompson River bridges

Four historic bridges on the Big Thompson River in Larimer County, Colorado survived its flood of 1976, but since have lost most of their historic integrity. They were built in 1933 and 1937. All four were listed on the National Register of Historic Places in 2002, and two were delisted in 2010.

The four bridges:

All four were camelback pony truss bridges that were designed by the Colorado Department of Highways and fabricated by Midwest Steel & Iron Works. Bridges III and IV were put together by Lawrence Construction Company in 1933, and bridges I and II were put together by contractor M.E. Carlson four years later.

The bridges were deemed significant for representing transportation and for their preserved structure. Bridges I and II were removed from the National Register on November 29, 2010. Delistings from the NRHP usually occur when a listed building or other structure is demolished or if its historic integrity is otherwise severely compromised. Bridges III and IV have been substantially renovated in place so far that their camelback truss structures are entirely gone, but they currently remain on the Register.

The four bridges were identified as conforming to terms defined for historic bridge notability as defined in a 2000 study.

The bridge, near Estes Park, had pedestrian sidewalks cantilivered from the outside.40°22′49″N 105°28′19″W / 40.38028°N 105.47194°W / 40.38028; -105.47194 (Big Thompson River Bridge I)

This bridge was structurally the same as its predecessor bridge.40°23′22″N 105°27′49″W / 40.38944°N 105.46361°W / 40.38944; -105.46361 (Big Thompson River Bridge II)