State Route 70 (SR 70) is a state highway in the U.S. state of California, connecting SR 99 north of Sacramento with U.S. Route 395 (US 395) near Beckwourth Pass (lowest in the Sierra Nevada) via the Feather River Canyon. Through the Feather River Canyon, from SR 149 to US 395, SR 70 is the Feather River Scenic Byway, a Forest Service Byway that parallels the ex-Western Pacific Railroad's Feather River Route.

The Beckwourth Trail was the earliest predecessor of SR 70, which was a spur of the California Trail. This was followed by the railroad, mostly built on the route of the trail; a dirt road was needed for construction that was later converted into part of the present state highway. Construction on the highway began in 1928, which involved the boring of three tunnels. Previously, the road was signed as U.S. Route 40 Alternate, crossing the Sierra Nevada at a lower elevation than Donner Pass on US 40, now Interstate 80 (I-80). The road was renumbered SR 70 in the 1964 state highway renumbering. Today, portions of SR 70 have been upgraded to a four-lane expressway, and even a freeway in a few locations.

Route description Route 70 is defined in section 370 of the California Streets and Highways Code. The definition omits the concurrency with Route 20 instead of duplicating that segment in the other route's definition in the code:

Route 70 is from: (a) Route 99 near Catlett Road to Route 20 in Marysville. (b) Route 20 in Marysville to Route 395 near Hallelujah Junction via Quincy and Beckwourth Pass.

State Route 70 begins at a partial interchange with SR 99 north of Sacramento, close to the Feather River Route rail line that parallels the entire highway, and heads north along a four-lane mix of expressway and freeway. Just north of the Bear River crossing / Yuba County line, in Plumas Lake, SR 70 becomes a freeway for the second time, which continues to just beyond the Yuba River in Marysville. Within that city, SR 70 makes two turns and overlaps SR 20 before heading north on a two-lane road, expanding to four lanes shortly thereafter. Another four-lane freeway begins south of SR 162 in Oroville, and ends at SR 149. SR 149 is a major connection northwest to SR 99, and became the straight-through movement when the construction to replace the intersection with an interchange was completed in November 2008. The State Scenic Highway portion of SR 70 begins at SR 149, which is where SR 70 turns northeast out of the Sacramento Valley and into the mountains. The short SR 191 spurs north to Paradise, while SR 70 crosses the West Branch Feather River on the double-decker West Branch Bridge, with the Feather River Route below. A short four-lane section runs over the bridge towards Jarbo Gap, where the present SR 70 merges with the old road (Dark Canyon Road) that was used before the Feather River was dammed to create Lake Oroville in the 1960s.Google Maps street maps and USGS topographic maps, accessed December 2007 via ACME Mapper

After crossing through Jarbo Gap, SR 70 drops down into the canyon of the North Fork Feather River, which it follows almost to Quincy, usually on the opposite side from the Feather River Route; this results in two places where both transportation lines cross the river and each other. The first of these is the Pulga Bridge, an arch bridge that crosses over a lower railroad truss bridge; soon after are the highway's three tunnels through rock formations in the canyon. After a fair distance through the canyon, and that formed by the East Branch North Fork Feather River, SR 70 reaches the junction with State Route 89 near Paxton; Routes 70 and 89 overlap southeast from that point, where the East Branch splits into Indian Creek and Spanish Creek.

The highway heads southeast, partly along the latter creek, past Keddie to Quincy in the American Valley. It leaves the valley via Greenhorn Creek, passing the Feather River Route's Williams Loop and then following the small Estray Creek to Lee Summit, which the rail line passes under in the Spring Garden Tunnel. This brings SR 70 into the valley of the Middle Fork Feather River, which takes it southeast to Blairsden, where the State Scenic Highway ends and State Route 89 splits to the south, and then east, through the Plumas National Forest, to Portola and Beckwourth. The large Sierra Valley begins at the latter community, and SR 70 heads almost directly across, passing the north end of SR 49 at Vinton and the south end of SR 284 at Chilcoot before crossing Beckwourth Pass, which the railroad takes the Chilcoot Tunnel under, and descending slightly to end at U.S. 395 at Hallelujah Junction.

The portion of SR 70 west of State Route 89 near Blairsden is also eligible for the State Scenic Highway System, but has not been designated as such by Caltrans. The entire route is part of the California Freeway and Expressway System, though it is mostly two lanes. SR 70 south of SR 149 is part of the National Highway System, a network of highways that are considered essential to the country's economy, defense, and mobility by the Federal Highway Administration. All of SR 70 is designated as the Feather River Scenic Byway, a National Forest Scenic Byway.

History

Trails James Beckwourth opened the Beckwourth Trail over Beckwourth Pass in 1851, crossing the Sierra Nevada at a lower elevation than the existing Donner Pass route of the California Trail. This split from the Truckee Route of the California Trail near Reno and roughly followed the present SR 70 to Quincy, but, rather than passing through the Feather River Canyon, it followed Oroville-Quincy Highway along ridges to Bidwell's Bar.The Beckwourth Trail: A Route to the Gold Country, accessed December 2007 A company was incorporated on July 23, 1855, to build the Quincy and Spanish Ranch Wagon Road, which bypassed the older trail from Quincy west to Spanish Ranch and began collecting tolls in November. The Pioneer Wagon Road, another toll road, was built in 1856 and 1857, continuing the improvements southwest to Buckeye (just before the Butte County line). An 1866 law authorized Plumas County to improve the portion from Quincy east to Beckwourth. The county also improved the road east from Beckwourth over the pass as part of the Red Clover Wagon Road, which began at Genesee and was completed in the 1870s.Illustrated History of Plumas, Lassen & Sierra Counties, 1882

The Western Pacific Railroad completed its main line into California in 1909. This followed the old Beckwourth Trail east of Quincy, but to the west it reached Oroville and Marysville via the Feather River Canyon. While building the railroad, the Utah Construction Company had created a dirt road through the canyon to assist with construction; citizens created the Plumas County Road Association in 1911 to push for improvements to this roadway and creation of a year-round route between Oroville and Quincy (the existing route over the ridges was closed for at least four months each winter). The first state highway bond issue, passed by the state's voters in 1910, included a Route 30 connecting Oroville with Quincy. Plumas County surveyor Arthur W. Keddie surveyed the Feather River Canyon route for the California Highway Commission in 1913, but the state announced in 1916 that the existing ridge route would be improved. After much debate, the state legislative road committee included the statement that this route would follow the Feather River in the 1919 amendment authorizing a third bond issue;: "Feather river route Oroville to Quincy" instead of keeping it as Route 30, the Highway Commission changed the designation to an extension of the short Richvale-Oroville (now SR 162) Route 21, which was also part of the first bond issue.Howe & Peters, Engineers' Report to California State Automobile Association Covering the Work of the California Highway Commission for the Period 1911-1920, pp. 11-14Jim Young, Plumas County: History of the Feather River Region, Arcadia Publishing, 2003, pp. 65-68

Modern route

Construction began on July 1, 1928, with convict labor for the easier portions and contractors for the remainder, as well as bridges and tunnels, but was slowed by the Great Depression. On the most difficult portion, between Cresta and Rock Creek, three tunnels had to be built at Arch Rock, Grizzly Dome, and Elephant Butte; at the former two, surveyors had to hang out on rope over steep granite slopes, and rockslides repeatedly caused delays. The commission dedicated the road at a ceremony at Grizzly Dome, halfway between the ends, on August 14, 1937. Construction had cost $8.15 million for 78 miles (126 km) of new road. The remainder of the old trail from Quincy to the junction with Route 29 (now U.S. 395) east of Beckwourth Pass was added to the state highway system in 1931 as an extension of Route 21,: "Quincy to State Highway Route 29, near Chats." and was paved by 1936. A new Route 87 was created in 1933, stretching from Woodland via Marysville and Oroville to Route 3 (State Route 99) southeast of Chico, including the present SR 70 between Marysville and Oroville.: "State Highway Route 3 near Chico to State Highway Route 21 near Oroville." "State Highway Route 15 near Marysville to State Highway Route 21 near Oroville." "State Highway Route 7 near Woodland to State Highway near Yuba City." Route 87 from Woodland to Oroville and Route 21 from Oroville to east of Beckwourth Pass became a new State Route 24 in 1934; State Route 24 was extended southwest from Woodland to Oakland by the end of 1937.Fresno Bee, New Bay Area Tunnel is Modern Traffic Unit, December 15, 1937

U.S. Route 40 Alternate

In 1954,Reno Evening Gazette, April 28, 1954: "The complete caravan will then proceed up the Feather river canyon and into Reno via Highway 24, the Feather river route."Reno Evening Gazette, July 16, 1954: "...located on Alternate U.S. 40, former State Route 24, about two miles (3 km) east of Portola." the original part of State Route 24 was replaced by U.S. Route 40 Alternate, which continued south on U.S. 99W from Woodland to Davis and southeast on U.S. 395 to Reno, Nevada to join U.S. 40 at both ends.H.M. Gousha Company, California , 1955 A direct route from Marysville south to Sacramento was added to the state highway system in 1949 as Route 232,: "Route 207 is from Sacramento to Marysville...": renumbered Route 207 to 232, since a Route 207 already existed and later became part of a rerouted State Route 24.H.M. Gousha Company, California, 1963 The U.S. 40 Alternate designation was short-lived, and was mostly replaced by State Route 70 in the 1964 renumbering. Southwest of Marysville, former U.S. 40 Alternate instead became State Route 113, and SR 70 ran south along former State Route 24 (Route 232) to a point north of Sacramento, where the new State Route 99 came in from the northwest and continued south.: "Route 70 is from Route 99 near Catlett Road to Route 395 near Hallelujah Junction via Quincy and Beckwourth Pass." Despite SR 70 always ending at State Route 99, it was once signed along State Route 99 (El Centro Road, Garden Highway, and the Jibboom Street Bridge) to Sacramento.H.M. Gousha Company, Sacramento, California , 1967

Modern alignments