The South Fork Eel River Viaduct is an abandoned portion of the early Redwood Highway located between Leggett and Confusion Hill in Mendocino County. This span was constructed in 1923 and is more popularly known as "The Slab." The South Fork Eel River Viaduct is 525 feet in length and served as part of US Route 101 from 1926 until 1982. The structure was ultimately bypassed by an inland cut and left abandoned. Part 1; the history of the South Fork Eel River Viaduct The South Fork Eel River Viaduct is a former component of the early Redwood Highway located between Leggett and Confusion Hill. This structure is often referred to as the "The Slab" by abandoned highway enthusiasts. The history of what would become the Redwood Highway (later US Route 101) begins with the approval of the 1909 First State Highway Bond Act . The First State Highway Bond Act was approved by voters during 1910 and was the genesis point of some of the most notable hig...
The Hacienda Bridge was constructed by the Northwestern Pacific Railroad in 1914 at the Russian River near Hacienda siding. During the mid 1930s the rails atop this structure were removed from this span and Sonoma County would repurpose it was part of River Road in 1945. This truss was widened to two-lanes in 1948 still carries River Road over the Russian River. The history of the Hacienda Bridge The Hacienda Bridge was constructed by the Northwestern Pacific Railroad in 1914 near Hacienda siding. The span was part of the Fulton and Guerneville Branch which originated at the mainline westward from Fulton. The Fulton and Guerneville Branch was originally completed in 1872 as a standard gauge spur line the San Francisco & Northern Pacific Railroad. The line was eventually extended to Cazadero by 1877. The Fulton and Guerneville Branch along with the Hacienda Bridge (marked via blue pin) can be seen east of Guerneville on the 1920 United States Geological Survey map of Healdsbur...