California State Route 128
|Defined by Streets and Highways Code § 428|
|Maintained by Caltrans|
|Length:||120.52 mi (193.96 km)|
|West end:||SR 1 near Albion|
| US 101 in Cloverdale
SR 29 in Calistoga
|East end:||I‑505 in Winters|
Route 128 begins at Route 1 near the mouth of the Navarro River at the Pacific Ocean. The highway travels upriver through the coast redwood forests of Navarro River Redwoods State Park and through the vineyards and apple orchards of the Anderson Valley to Boonville. Route 253 terminates into Route 128 at the south end of Boonville. Leaving Boonville, Route 128 climbs out of the Navarro River watershed and crosses the Yorkville Highlands before descending into the Russian River watershed, arriving at Cloverdale in the Alexander Valley, where the highway joins U.S. Route 101 heading south. A few miles later, at Geyserville, Route 128 separates from U.S. 101 and crosses Knights Valley on the way to Napa Valley, where it joins Route 29 at Calistoga. After passing through the town of St. Helena, Route 128 splits from Route 29 at Rutherford and climbs east over dry ridges above Lake Berryessa to the Sacramento Valley. In Winters, the route's constructed portion ends at Interstate 505. By its legal definition, the route continues 14 mi (23 km) east to Route 113 at Davis and Interstate 80, but this segment is currently not constructed.
The section of Route 128 through Navarro River Redwoods State Park is often closed in winter storms due to flooding. Two slower alternate routes are available: the Philo-Greenwood road connects Route 1 near Elk to Route 128 near Hendy Woods State Park, a few miles north of Philo; another alternate route is the Comptche-Ukiah Road, which intersects Route 1 just south of the town of Mendocino and runs inland to Comptche, and departs Comptche on Flynn Creek Road, intersecting Route 128 just up river from the seasonal flood gate closing the highway.
Except where prefixed with a letter, postmiles were measured on the road as it was in 1964, based on the alignment that existed at the time, and do not necessarily reflect current mileage. R reflects a realignment in the route since then, M indicates a second realignment, L refers an overlap due to a correction or change, and T indicates postmiles classified as temporary (for a full list of prefixes, see the list of postmile definitions). Segments that remain unconstructed or have been relinquished to local control may be omitted. The numbers reset at county lines; the start and end postmiles in each county are given in the county column.
|0.00||SR 1 – Mendocino, Fort Bragg, Point Arena||West end of SR 128|
|Boonville||29.58||SR 253 east – Ukiah|
|North Cloverdale Boulevard (US 101 Bus. south, SR 128 Bus. east) – Cloverdale||West end of US 101 Bus. overlap|
|US 101 north (Redwood Highway) – Eureka||Interchange; east end of US 101 Bus. overlap; west end of US 101 overlap|
|West end of freeway on US 101|
|Cloverdale||R51.62[N 1]||520||Citrus Fair Drive|
|R50.43[N 1]||519||South Cloverdale Boulevard (US 101 Bus. north, SR 128 Bus. west)|
|R49.05[N 1]||518||Dutcher Creek Road – Stewarts Point|
|Geyserville||East end of freeway on US 101|
|US 101 south (Redwood Highway) / Canyon Road – San Francisco||Interchange; east end of US 101 overlap|
|2.66||Tubbs Lane – Middletown, Lakeport|
|Calistoga||3.62||Petrified Forest Road – Santa Rosa|
|SR 29 north (Lincoln Avenue) – Lakeport, Downtown Calistoga||West end of SR 29 overlap|
|SR 29 south – Napa||East end of SR 29 overlap|
|7.37||Silverado Trail – St. Helena, Calistoga, Napa|
|11.28||Chiles Pope Valley Road – Pope Valley|
|23.90||SR 121 south (Monticello Road) – Napa|
|No major junctions|
|Winters||8.77||Railroad Avenue – Madison, Downtown Winters|
|9.84||I‑505 – Redding, Vacaville||Interchange; east end of SR 128|
|9.84||CR E6 (Russell Boulevard) – Davis||Continuation beyond I-505|
|1.000 mi = 1.609 km; 1.000 km = 0.621 mi
California State Route 128 was originally signed as State Route 28. In 1952 it was renumbered State Route 128, permitting the route around Lake Tahoe to be numbered as Route 28 in coordination with Nevada Route 28.
- January 1, 2006 California Log of Bridges on State Highways
- Florsheim, Joan L.; Mount, Jeffrey F.; Rutten, Luke T. (2000), "Effect of baselevel change on floodplain and fan sediment storage and ephemeral tributary channel morphology, Navarro River, California", Earth Surface Processes and Landforms 26 (2): 219–232, doi:10.1002/1096-9837(200102)26:2<219::AID-ESP169>3.0.CO;2-0
- Mendocino Coast Properties Map and Directions
- California Department of Transportation. "State Truck Route List". Sacramento: California Department of Transportation. Archived from the original (XLS file) on June 30, 2015. Retrieved June 30, 2015.
- California Department of Transportation, Log of Bridges on State Highways, April 2008
- California Department of Transportation, All Traffic Volumes on CSHS, 2007
- California Department of Transportation, California Numbered Exit Uniform System, U.S. Route 101 Freeway Interchanges