![]() Map of western California with SR 121 highlighted in red | ||||
Route information | ||||
Maintained by Caltrans | ||||
Length | 33.567 mi [1] (54.021 km) | |||
Major junctions | ||||
South end | ![]() | |||
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North end | ![]() | |||
Location | ||||
Country | United States | |||
State | California | |||
Counties | Sonoma, Napa | |||
Highway system | ||||
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State Route 121 (SR 121) is a state highway in the U.S. state of California. It runs through the Wine Country region of Sonoma and Napa counties. Its southern terminus is at State Route 37 at Sears Point, and its northern terminus is at State Route 128 near Lake Berryessa. SR 121 passes through the Carneros region of the southern Sonoma Valley and Napa Valley.
The route begins at SR 37 in Sears Point, and then runs past the Tolay Lake basin and across Tolay Creek near Infineon Raceway. As it continues northward through Sonoma County, it meets SR 116, where it then veers east. SR 121 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 near Lake Berryessa.
SR 121 is part of the California Freeway and Expressway System, [2] but is not part of the National Highway System, [3] a network of highways that are considered essential to the country's economy, defense, and mobility by the Federal Highway Administration. [4] SR 121 is eligible to be included in the State Scenic Highway System, [5] but it is not officially designated as a scenic highway by the California Department of Transportation. [6] The California Legislature named the route Carneros Highway from its southern terminus to its junction with SR 29 in Napa, after the Carneros settlement. [7] The stretch in Sonoma County between SR 37 and SR 116 runs along Arnold Drive, and along Fremont Drive between SR 116 and the Napa County line.
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. [8]
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 to an overlap due to a correction or change, and T indicates postmiles classified as temporary ( ). [1] 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 [9] [10] | Destinations | Notes | |
---|---|---|---|---|---|
Sonoma SON 0.00-11.62 | Sears Point | 0.00 | ![]() | South end of SR 121 | |
| 6.69 | ![]() ![]() | |||
Schellville | 7.44 | ![]() ![]() | South end of SR 12 overlap | ||
| R10.79 | Napa Road | |||
Napa NAP 0.00-22.08 | Napa | R4.47 R8.66 [N 1] | ![]() ![]() ![]() ![]() | North end of SR 12 overlap; south end of SR 29 overlap | |
South end of freeway on SR 29 | |||||
R10.30 [N 1] R4.47 | North end of freeway on SR 29 | ||||
![]() ![]() | Interchange; north end of SR 29 overlap; SR 29 exit 16 | ||||
6.01 | ![]() ![]() | ||||
6.55 | Soscol Avenue north – Downtown Napa | ||||
| 9.40 | Silverado Trail, Trancas Street | |||
| 16.07 | Wooden Valley Road – Fairfield | |||
| 22.08 | ![]() | North end of SR 121 | ||
1.000 mi = 1.609 km; 1.000 km = 0.621 mi
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State Route 138 is an east–west state highway in the U.S. state of California that generally follows the northern foothills of the San Gabriel Mountains and the western Mojave Desert. The scenic highway begins in the west at its junction with Interstate 5 located south of Gorman in the Sierra Pelona Mountains, continues eastward through the Antelope Valley and Cajon Pass, to its junction with State Route 18 in the east, located in the San Bernardino Mountains south of Crestline.
State Route 37 is a state highway in the U.S. state of California that runs 21 miles (34 km) along the northern shore of San Pablo Bay. It serves as a vital connection in the North Bay region of the San Francisco Bay Area, running from U.S. Route 101 in Novato, through northeastern Marin County, and the southern tips of both Sonoma and Solano Counties to Interstate 80 in Vallejo. Sonoma Raceway and Six Flags Discovery Kingdom are accessible from Highway 37.
State Route 84 is a state highway in the U.S. state of California that consists of two unconnected segments, one in the San Francisco Bay Area and the other primarily in the Sacramento–San Joaquin River Delta area.
State Route 116 (SR 116) is a state highway in the U.S. state of California in Sonoma County. The route runs from SR 1 on the Pacific coast near Jenner to SR 121 south of Sonoma.
State Route 18 is a state highway in the U.S. state of California. It serves as a primary route into the San Bernardino Mountains, both from the Riverside–San Bernardino metropolitan area from the south and the Mojave Desert from the north. SR 18 runs from State Route 210 in San Bernardino to State Route 138 in Llano. It has two discontinuities: one in Big Bear Lake, the other in Victorville.
State Route 12 is a state highway in the U.S. state of California that travels in an east–west direction from State Route 116 in Sebastopol in Sonoma County to State Route 49 just north of San Andreas in Calaveras County. The route connects the Sonoma and Napa valleys with the Sacramento–San Joaquin River Delta and the Sierra Foothills. It is constructed to freeway standards from the Fulton Road/South Wright Road stoplight in Santa Rosa, to its partial interchange with Farmers Lane.
State Route 68 is a state highway in the U.S. state of California, located entirely in Monterey County. It runs from Asilomar State Beach in Pacific Grove to U.S. Route 101 in Salinas. The approximately 20-mile (32 km) long highway serves as a major route between the Monterey Peninsula and Salinas.
State Route 33 is a north–south state highway in the U.S. state of California. It runs north from U.S. Route 101 in Ventura through the Transverse Ranges and the western side of the San Joaquin Valley to Interstate 5 at a point east of Tracy. SR 33 replaced part of U.S. Route 399 in 1964 during the "great renumbering" of routes. In the unincorporated sections of Kern County it is known as the West Side Highway. In addition, the California Legislature designated the entire Kern County portion as the Petroleum Highway in 2004. The southernmost portion in Ventura is a freeway known as the Ojai Freeway, while it is known as the Maricopa Highway from Ojai to Maricopa.
State Route 29 is a state highway in the U.S. state of California that travels from Interstate 80 in Vallejo north to State Route 20 in Upper Lake. It serves as the primary road through the Napa Valley, providing access to the Lake County region to the north and the rest of the San Francisco Bay Area to the south.
State Route 28 is a state highway in the U.S. state of California that travels along the northern shore of Lake Tahoe, starting at Route 89 in Tahoe City and ending at the Nevada state border, whereupon it becomes Nevada State Route 28.
State Route 36 is an east–west state highway in the U.S. state of California that is routed from U.S. Route 101 in Humboldt County to U.S. Route 395 just east of Susanville in Lassen County. The highway passes through Red Bluff, the county seat of Tehama County, on the northern edge of the Sacramento Valley. The portion of SR 36 travelling past Lassen Volcanic National Park and Lake Almanor is part of the Volcanic Legacy Scenic Byway, a National Scenic Byway. Also, Route 36 between Alton and Susanville is a designated Blue Star Memorial Highway.
State Route 166 is a state highway in the U.S. state of California. It connects the Central Coast to the southern San Joaquin Valley, running from State Route 1 in Guadalupe and through Santa Maria in Santa Barbara County to State Route 99 in Mettler in Kern County.
State Route 44 is a state highway in the U.S. State of California that travels in an east–west direction from State Routes 273 and 299 in Redding to Lassen Volcanic National Park before ending at State Route 36 west of Susanville. This final portion, between the park and its terminus, is part of the Volcanic Legacy Scenic Byway, a National Scenic Byway.
State Route 45 is a state highway in the U.S. State of California that travels in a north–south direction in the Sacramento Valley from Route 113 in Knights Landing to Route 32 in Hamilton City.
State Route 53, also known as the Clearlake Expressway for part of its length, is a state highway in the U.S. state of California that runs in a north–south direction in Lake County east of Clear Lake, It connects SR 29 and SR 20 via the city of Clearlake.
State Route 128 is a state highway in the U.S. state of California, connecting the Mendocino coast to the Sacramento Valley, through the state's Wine Country. It runs from State Route 1 near Albion to Interstate 505 in Winters.
State Route 136 is a state highway in the U.S. state of California, running along the northern edge of Owens Lake in Inyo County from U.S. Route 395 in Lone Pine to State Route 190.
State Route 167 is a state highway in the U.S. state of California in Mono County. From U.S. Route 395, SR 167 runs along Pole Line Road north of Mono Lake eastward to the Nevada state line where it meets Nevada State Route 359. This road runs almost completely straight, and can be seen almost 15 miles (24 km) into the distance as a straight line.
State Route 200 is a state highway in the U.S. state of California near Arcata in Humboldt County. It is a cut-off connecting U.S. Route 101 and State Route 299. It runs along the north bank of the Mad River, to the north of the 101-299 junction. It is also known as North Bank Road.
State Route 221 is a state highway in the U.S. state of California that runs in and just outside the City of Napa, providing access to Napa Valley College and Napa State Hospital. The highway's southern terminus is with State Route 12 and State Route 29 outside the southeast corner of the city, and its northern terminus is at State Route 121 inside the city. SR 221 forms part of the Napa-Vallejo Highway with SR 29.