1 vote

Black Canyon Road Bridge


Photo taken by Historic American Engineering Record

View photos at Library of Congress

BH Photo #159211


The Black Canyon Road Bridge is a concrete arch bridge that exemplifies the technological innovation known as the Thomas Three-Hinge System. The bridge is one of only three existing examples designed by William Thomas in California. It is remarkably unaltered and its original setting is still intact. The bridge was determined eligible for the National Register of Historic Places during a 1987 California Historic Bridges Survey by the California Department of Transportation.

-- Historic American Engineering Record


Open spandrel Concrete arch bridge over Santa Ysabel Creek on Black Canyon Road
San Diego County, California
Bypassed and kept open to pedestrians only
Built 1913
- Thomas & Post (Design Firm)
- William M. Thomas (Design Engineer)
Open spandrel concrete deck arch
Length of largest span: 80.1 ft.
Total length: 125.0 ft.
Deck width: 20.0 ft.
Eligible for the National Register of Historic Places
Approximate latitude, longitude
+33.12389, -116.80000   (decimal degrees)
33°07'26" N, 116°47'60" W   (degrees°minutes'seconds")
Approximate UTM coordinates
11/518657/3665039 (zone/easting/northing)
Quadrangle map:
Average daily traffic (as of 1991)
Inventory numbers
CA 57C-361 (California bridge number)
BH 11406 (Bridgehunter.com ID)
Inspection report (as of July 2009)
Overall condition: Poor
Superstructure condition rating: Poor (4 out of 9)
Substructure condition rating: Poor (4 out of 9)
Deck condition rating: Serious (3 out of 9)
Sufficiency rating: 16.5 (out of 100)
View more at BridgeReports.com

Update Log 

  • April 30, 2011: Updated by Craig Philpott: corrected spelling
  • June 3, 2010: Updated by Craig Philpott: refined design
  • March 27, 2010: New photos from Jason Smith


  • Jason Smith - flensburg [dot] bridgehunter [dot] av [at] googlemail [dot] com
  • Craig Philpott - craigphilpott63 [at] gmail [dot] com
  • HAER CA-264 - Black Canyon Road Bridge, Spanning Santa Ysabel Creek at intersection of Black Canyon & Sutherland Dam Roads, Ramona, San Diego County, CA