California State Route 121
|Defined by S&HC § 421|
|Maintained by Caltrans|
|Length:||33.57 mi (54.02 km)|
|South end:||SR 37 at Sears Point|
| SR 12 near Sonoma
SR 29 in Napa
|North end:||SR 128 near Lake Berryessa|
State Route 121 (SR 121) is a California state highway in the Wine Country that runs northerly from its junction with State Route 37 at Sears Point, past the Tolay Lake basin and across Tolay Creek near Infineon Raceway, veers east at a junction with State Route 116 and Bonneau Road at Schellville, runs eastward through the Carneros region of the southern Sonoma Valley and Napa Valley (concurrent first with State Route 12, then with State Route 29), then northeastward to end near Lake Berryessa in Napa County.
The California Legislature named the route Carneros Highway from its southern terminus to its junction with Route 29 in Napa. The stretch between the junctions with Route 116 and Napa Road near the Sonoma/Napa county line is known locally as Fremont Drive. Addresses along the stretch between routes 37 and 116 sometimes use the postal address Arnold Drive, even though that name officially applies only to the county road north of 116.
The route begins at SR 37 in Sears Point. As it continues northward through Sonoma County, it meets SR 116. It then enters Schellville, where it begins a short overlap with SR 12. Upon leaving, it begins another overlap with SR 29, which happens to be a freeway, in Napa County. When it leaves, it continues northward and meets SR 221 in Napa. As it leaves the city, it continues northward for several miles before reaching its north end at SR 128.
The section from SR 37 to SR 29 in Napa remains virtually unchanged since its definition in 1963. The northern section, however, was slightly altered since its definition the same year due to a realignment of various other freeways.
Except where prefixed with a letter, postmiles were measured on the road as it was in 1964, and do not necessarily reflect current mileage. R reflects a realignment in the route since then, and T indicates postmiles classified as temporary. The numbers reset at county lines; the start and end postmiles in each county are given in the county column.
|Sears Point||0.00||SR 37 – Vallejo, Novato|
|6.69||SR 116 west (Arnold Drive) / Bonneau Road – Glen Ellen, Petaluma|
|Schellville||7.44||SR 12 west (Broadway) – Sonoma, Boyes Hot Springs, Glen Ellen||South end of SR 12 overlap|
|SR 29 south / SR 12 east – American Canyon, Vallejo, Fairfield||North end of SR 12 overlap; south end of SR 29 overlap|
|South end of freeway on SR 29|
|North end of freeway on SR 29|
|SR 29 north / Imola Avenue west – Calistoga||Interchange; north end of SR 29 overlap|
|6.01||SR 221 south (Soscol Avenue south) / Imola Avenue east – Vallejo|
|6.55||Soscol Avenue north – Downtown Napa|
|9.40||Silverado Trail, Trancas Street|
|16.07||Wooden Valley Road – Fairfield|
|22.08||SR 128 – Winters, Lake Berryessa, Rutherford|
|1.000 mi = 1.609 km; 1.000 km = 0.621 mi
- Indicates that the postmile represents the distance along SR 29 rather than SR 121.
- California Department of Transportation, State Truck Route List (XLS file), accessed February 2008
- CA Codes (shc:250-257)
- CA Codes (shc:260-284)
- "Officially Designated State Scenic Highways and Historic Parkways". California Department of Transportation. December 7, 2007. Retrieved June 23, 2011.
- Faigin, Daniel P. "California Highways:Routes 121 through 128". Retrieved 2010-04-27.
- California Department of Transportation, Log of Bridges on State Highways, April 2008
- California Department of Transportation, All Traffic Volumes on CSHS, 2007