California State Route 128

State Route 128
Map of western California with SR 128 highlighted in red
Route information
Defined by Streets and Highways Code § 428
Maintained by Caltrans
Length:	120.52 mi[1] (193.96 km)
Major junctions
West end:	SR 1 near Albion
	US 101 in Cloverdale SR 29 in Calistoga
East end:	I-505 in Winters
Highway system
State highways in California Interstate U.S. State Pre-1964 History Unconstructed Deleted Freeway Scenic ← SR 127 SR 129 →

State Route 128 (SR 128) is a state highway in the U.S. state of California, connecting the Mendocino coast to the Central Valley through the state's Wine Country.

Route description

A relatively straight section of State Route 128 near Hendy Woods State Park.

Highway marker showing cosign of US 101 and California Route 128.

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.^[2] 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;^[3] 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.

History

The main road through the Anderson Valley to the mouth of the Navarro River, and from there up the coast to Fort Bragg, was originally called the Navarro Highway; it follows the approximate route of the present Route 128 and Route 1 through Mendocino County. Even earlier, the road followed the Navarro Ridge, to the north of the present alignment, instead of staying at the river level.^[4] By 1938, the last stretches of old winding roadway near the present location of Navarro were replaced by a straighter alignment, taken over from a disused logging railway line.^[5]

Before being numbered as California State Route 128, the highway was signed as State Route 28. In 1952 it was renumbered State Route 128, permitting a different highway around Lake Tahoe to be numbered as Route 28 to coordinate its numbering with Nevada Route 28.^[6]

Major intersections

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).^[7] 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.

County	Location	Postmile [7][8][9]	Exit [10]	Destinations	Notes
Mendocino MEN 0.00-50.90	​	0.00		SR 1 – Mendocino, Fort Bragg, Point Arena	West end of SR 128
	Boonville	29.58		SR 253 east – Ukiah
Sonoma SON 0.00-24.76	​	​		North Cloverdale Boulevard (US 101 Bus. south, SR 128 Bus. east) – Cloverdale	West end of US 101 Bus. overlap
	​	L4.86 R53.40[N 1]		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
	​	R47.85[N 1]	517	Asti
	Geyserville	​	East end of freeway on US 101
		43.37[N 1] L4.86		US 101 south (Redwood Highway) / Canyon Road – San Francisco	Interchange; east end of US 101 overlap
Napa NAP 0.00-34.27	​	2.66		Tubbs Lane – Middletown, Lakeport
	Calistoga	3.62		Petrified Forest Road – Santa Rosa
		4.55 36.89[N 2]		SR 29 north (Lincoln Avenue) – Lakeport, Downtown Calistoga	West end of SR 29 overlap
	Rutherford	24.60[N 2] 4.56		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
Solano SOL 0.00-0.75	No major junctions
Yolo YOL 0.00-9.84	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       Concurrency terminus

References

External links

• California @ AARoads - State Route 128
• Caltrans: Route 128 highway conditions
• California Highways: SR 128