2 votes

Eel River Viaduct


Eel River Viaduct

Looking East

Photo taken by Craig Philpott in May 2010


BH Photo #164944


Street View 


Abandoned concrete stringer bridge over Sidehill on Old Hwy 101
Mendocino County, California
Concrete post and beam sidehill viaduct on old alignment of Hwy 101.
Total length: 525.0 ft.
Deck width: 24.0 ft.
Approximate latitude, longitude
+39.90507, -123.75665   (decimal degrees)
39°54'18" N, 123°45'24" W   (degrees°minutes'seconds")
Approximate UTM coordinates
10/435323/4417494 (zone/easting/northing)
Quadrangle map:
822 ft. above sea level
Inventory number
BH 45223 (Bridgehunter.com ID)


Abandoned (3,650)
Beam (15,718)
California (2,593)
Concrete stringer (800)
Have street view (26,949)
Mendocino County, California (72)
Owned by state (15,994)
Total length 500-1000 feet (2,871)
US 101 (105)

Update Log 

  • March 22, 2011: New photos from Michael Goff
  • September 18, 2010: New Street View added by Craig Philpott
  • May 10, 2010: Added by Craig Philpott


  • Craig Philpott - craigphilpott63 [at] gmail [dot] com
  • HAER CA-269 - Redwood National & State Parks Roads, California coast from Crescent City to Trinidad, Crescent City vicinity, Del Norte, CA
  • Mike Goff - michael [dot] goff [at] hotmail [dot] com


Eel River Viaduct
Posted May 7, 2019, by Rick Donaldson (mgy2 [at] aol [dot] com)


I did a little research on the subject viaduct to determine when it was bypassed by the present alignment of Highway 101. Based on a newspaper article in the Ukiah Daily Journal, dated August 17, 1982, the bypass around the old viaduct, sometimes called "the Slab" was scheduled to be completed by August 19, 1982, but was opened to traffic by August 17th that year. I drove on the old viaduct many times while attending Humboldt State University from 1972 to 1974.

Rick Donaldson

Spokane, WA

Eel River Viaduct
Posted October 11, 2018, by MFT (matsutwo [at] gmail [dot] com)

From historicaerials.com, the southern hill portion is still in use on their 1968 photo. The next available image is in 1993, where it looks like the northern road is in place. Unfortunately that's a 25 year window, at least that narrows it down a little.

Eel River Viaduct on Hwy. 101 North of Leggett, CA.
Posted November 22, 2015, by Eldon G. Whitehead (egwhitehead [at] suddenlink [dot] net)


Some of us has a question for you about the old Eel River Hwy. 101 Viaduct in Mendocino County, CA. Could you tell us when the new section of Highway was opened and when they closed down the sidehill portion? We would appreciate it very much and would answer some questions from us old timers who drove over this section all of the time.

Thanks for your time in this matter.

Eldon G. Whitehead,

fortuna, CA.