California State Route 120

State Route 120 marker
State Route 120
Map
SR 120 highlighted in red; the gap represents the unofficial segment through Yosemite National Park
Route information
Maintained by Caltrans
Length152.562 mi[1] (245.525 km)
(Does not include the portion in Yosemite)
Existed1934–present
Tourist
routes
  • Tioga Road/Big Oak Flat Road
  • Lee Vining Canyon Scenic Byway
RestrictionsSegments through Tioga Pass, and between Mono Lake and Benton, closed in winter
Major junctions
West end I-5 in Lathrop
Major intersections
East end US 6 at Benton
Location
CountryUnited States
StateCalifornia
CountiesSan Joaquin, Stanislaus, Tuolumne, Mono
Highway system
← SR 119→ SR 121

State Route 120 (SR 120) is a state highway in the central part of California that connects the San Joaquin Valley with the Sierra Nevada, Yosemite National Park, and the Mono Lake area. It runs between Interstate 5 (I-5) in Lathrop and U.S. Route 6 (US 6) in Benton, traversing four counties over a distance of approximately 153 miles (246 km). The route rises from near sea level in the Central Valley to 9,945 feet (3,031 m) at Tioga Pass, the highest highway pass in the state highway system.[1] While SR 120 is signed as a continuous route through Yosemite, the portion inside the park is federally maintained and is not included in the state route logs. The segment through Tioga Pass and the stretch between Mono Lake and Benton are subject to annual winter closure, typically from November through late May.[2]

The route has origins in the Gold Rush-era Big Oak Flat Road, a wagon road completed to Yosemite Valley in 1874. Through Yosemite, SR 120 follows Tioga Road, designated as both a National Scenic Byway and a National Forest Scenic Byway.[3]

Route description

Route 120 is defined in section 420 of the California Streets and Highways Code. The definition omits the federally maintained segment through Yosemite National Park, as well as the concurrency with US 395 instead of duplicating that segment in the other route's definition in the code:[4]

Route 120 is from:
(a) Route 5 near Mossdale to the west boundary of Yosemite National Park via the vicinity of Manteca and Oakdale, and via Big Oak Flat and Buck Meadows.
(b) The east boundary of Yosemite National Park to Route 395 near Mono Lake.
(c) Route 395 near Mono Lake to Route 6 near Benton Station.

SR 120 is part of the California Freeway and Expressway System.[5] Both the western portion and the eastern portion west of US 395 are part of the National Highway System (NHS), a network of highways that are considered essential to the country's economy, defense, and mobility by the Federal Highway Administration.[6][7] SR 120 is eligible to be included in the State Scenic Highway System but is not officially designated as a scenic highway by Caltrans.[8][9]

San Joaquin Valley

SR 120 near Oakdale in Stanislaus County

SR 120 begins at an interchange with I-5 near the Mossdale area of Lathrop, where it continues the alignment of Interstate 205 eastward as a four-lane freeway.[10] The freeway passes through the southern part of Manteca, serving several interchanges including the diverging diamond interchange at Union Road, the first of its kind constructed in California, which opened on November 25, 2020.[11] The freeway section, once known locally as "Blood Alley" for its high rate of head-on collisions on the original alternating-lane configuration, was subsequently improved with center median barriers.[10]

In eastern Manteca, SR 120 has a brief overlap with SR 99 before the freeway ends and the route continues east as a conventional two-lane highway. The road crosses the flat agricultural landscape of the San Joaquin Valley, passing through the small city of Escalon and continuing into Stanislaus County. At Oakdale, the route begins a concurrency with SR 108, which continues together as the highway leaves the valley floor and enters the Sierra Nevada foothills.

Sierra foothills

Night view looking west from New Priest Grade over Moccasin
Main Street in Chinese Camp, a Gold Rush settlement at the SR 120/SR 49 junction

East of Oakdale, the highway enters Tuolumne County and the landscape transitions from valley grasslands to oak-studded foothills. SR 108 splits off to the east toward Sonora at Yosemite Junction, while SR 120 turns southeast toward Chinese Camp, a Gold Rush settlement designated as California Historical Landmark No. 423.[12] At Chinese Camp, the route begins a concurrency with SR 49, the historic Mother Lode highway.

The combined SR 120/SR 49 crosses the Tuolumne River on the James E. Roberts Bridge, a 1,400-foot (430 m) structure spanning Don Pedro Reservoir. The bridge was built in 1970 to accommodate the new highway alignment created by the expansion of New Don Pedro Dam.[13] SR 49 separates near Moccasin, and SR 120 begins its climb into the mountains via Priest Grade. The New Priest Grade, opened in 1915, features over one hundred curves with a sustained 4-percent gradient, built as an alternative to the much steeper Old Priest Grade, which has a 17-percent grade.[14] Both grades are paved, but trailers and recreational vehicles are prohibited from Old Priest Grade, which has a 7,500 pounds (3,400 kg) weight limit.[15]

Above Priest Grade, SR 120 passes through Groveland and the adjacent community of Big Oak Flat, both founded during the Gold Rush in 1849.[16] These communities serve as the primary western gateway to Yosemite National Park along the SR 120 corridor. Continuing east, the route passes through Buck Meadows, the last community with traveler services before the park entrance, at an elevation of approximately 2,900 feet (880 m). A short distance beyond Buck Meadows, SR 120 reaches the western boundary of Yosemite National Park, where state maintenance ends and the road comes under federal jurisdiction.

Yosemite National Park

Big Oak Flat Entrance Station at the western park boundary
SR 120 as Tioga Road near Tenaya Lake in Yosemite National Park

Inside Yosemite National Park, state routes are federally maintained and are not included in the state route logs, although the park signs the routes at intersections. Visitors entering through the Big Oak Flat Entrance Station must pay a park entrance fee or present a valid pass.[17]

From the entrance station, the highway descends as Big Oak Flat Road toward Crane Flat, a junction at approximately 6,200 feet (1,900 m) elevation.[18] At Crane Flat, Big Oak Flat Road turns southeast toward Yosemite Valley, while SR 120 continues east as Tioga Pass Road (commonly Tioga Road).[19] Near Crane Flat, the road passes the Tuolumne Grove, one of three giant sequoia groves in the park.

Tioga Pass Entrance Station at the eastern park boundary
Tioga Road and Tenaya Lake viewed from Pywiack Dome

Tioga Road is a winding two-lane mountain road that traverses the park's subalpine high country. The road passes through forests of lodgepole pine and red fir, ascending gradually past Siesta Lake, White Wolf, and Yosemite Creek to Olmsted Point, a scenic overlook at 8,300 feet (2,500 m) with views of Tenaya Lake and the granite domes of the park's backcountry. The road then descends to Tenaya Lake before climbing again to Tuolumne Meadows, the largest subalpine meadow in the Sierra Nevada, at an elevation of approximately 8,600 feet (2,600 m).[20]

East of Tuolumne Meadows, Tioga Road ascends through Dana Meadows to Tioga Pass, at 9,945 feet (3,031 m) the highest highway pass in both the Sierra Nevada and the California state highway system.[21] Tioga Pass marks the park's eastern boundary, where the Tioga Pass Entrance Station collects fees from visitors entering from the east.[17] A winter closure gate is located near the entrance station; the road is typically closed from around November through late May, though exact dates vary by snowfall conditions.[2]

Tioga Road/Big Oak Flat Road is officially designated as both a National Scenic Byway and a National Forest Scenic Byway.[3] The Tioga Pass Road was designated as a California Historic Civil Engineering Landmark by the American Society of Civil Engineers in 2002.[22]

Eastern Sierra and Mono Basin

Tioga Road near Lee Vining, descending the eastern Sierra escarpment
US 395 through Lee Vining, at the SR 120 junction

East of Tioga Pass, the highway begins a dramatic descent through Lee Vining Canyon, dropping more than 3,000 feet (910 m) over approximately 12 miles (19 km) as it descends the steep eastern escarpment of the Sierra Nevada. This segment through Lee Vining Canyon is designated as the Lee Vining Canyon Scenic Byway, a National Forest Scenic Byway administered by the Inyo National Forest.[23]

The canyon road ends at the community of Lee Vining, on the southwestern shore of Mono Lake, where SR 120 meets US 395. The two routes share a concurrency southward for approximately 5 miles (8.0 km) to Mono Mills Junction, where SR 120 separates and continues east as Mono Mills Road.[24] This segment skirts the southern end of Mono Lake, providing access to the Mono Lake South Tufa area and the historical site of Mono Mills. The BLM Granite Mountain Wilderness lies immediately north of the route in this area.[25]

The highway crests Sagehen Summit before descending to its eastern terminus at a junction with US 6 in Benton. Both the Tioga Pass segment and the stretch between Mono Lake and Benton are subject to winter closure. The Tioga Road usually opens by the Memorial Day weekend at the end of May and typically closes for the winter sometime in November.[26][2]

History

Tioga Road, 1921
Historic postcard of Priest Grade, captioned "166 Turns in seven miles"

Origins and early roads

The origins of SR 120 lie in the Gold Rush era. The Big Oak Flat Road began as a pack trail from Stockton that became popular with prospectors around 1849, named after the mining settlement of Big Oak Flat through which it passed. By 1874, it had been improved to a wagon road extending to Yosemite Valley, serving as a major tourism and freight route.[27][28]

The Tioga Road was built in 1883 as a mining road to reach the Sheepherder and Tioga silver mines east of Tioga Pass. It became a private toll road, charging $2 per horse and rider. In 1915, Stephen Mather, who would become the first director of the National Park Service, purchased the road for $15,000 using his own funds and donations from the Sierra Club and the Modesto Chamber of Commerce, enabling public access through the park's high country.[29]

Legislative history

In 1921, the California State Assembly authorized San Joaquin County to transfer the county road connecting Manteca with then-Route 5 (now I-5) at Mossdale to the state.[30] It was numbered Route 66, as was a 1933 extension from Manteca east to Route 13 in Oakdale. Also in 1933, Route 40 was extended east from Mono Lake to Route 76 (US 6) at Benton.[31] The route from Manteca to Benton was marked as Sign Route 120 in 1934,[32] and was soon extended west to Mossdale,[33] replacing what had been part of U.S. Route 99W.[34]

New Tioga Road construction, 1958–1961

In 1956, the National Park Service developed plans to relocate the Big Oak Flat Road from Crane Flat to the park's eastern boundary, and reconstruct the unimproved central section of the Tioga Road. NPS management wanted to open the High Sierra section of the park to increased numbers of visitors and planned new facilities at Tuolumne Meadows. This brought fierce opposition from the Sierra Club, led by photographer Ansel Adams. Adams and his supporters opposed the blasting of a granite dome southwest of Tenaya Lake and the routing of the highway along the western shore of the lake. Internally, many Sierra Club members supported the project. The controversy created a serious rift in the relationship between the environmental organization and the National Park Service. The government ultimately proceeded with the project as originally planned, with only minor modifications.[35]

The present Big Oak Flat Road was constructed by the Bureau of Public Roads with Public Works Administration funding between 1935 and 1940.[36]

Manteca Bypass and safety improvements

The Manteca Bypass section of SR 120 opened in spring 1980 as a "super two" facility with limited overpasses. The original alternating-lane configuration earned the highway the nickname "Blood Alley" due to frequent head-on collisions. Local advocacy led to the installation of center median barriers separating the directions of traffic, substantially reducing fatalities. The bypass was subsequently widened to a full four-lane divided freeway.[10]

California's first diverging diamond interchange

On November 25, 2020, the first diverging diamond interchange in the state of California opened to traffic at the interchange with Union Road (exit 4) in Manteca.[11]

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 to an overlap due to a correction or change, and T indicates postmiles classified as temporary (for a full list of prefixes, see California postmile § Official postmile definitions).[39] 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.

CountyLocationPostmile
[1][37][38]		Exit
[40]		DestinationsNotes
San Joaquin
SJ R0.49-21.18		LathropR0.491 I-5 – San Francisco, Los Angeles, Stockton, SacramentoWestbound exit and eastbound entrance; signed as exits 1A (south) and 1B (north); west end of SR 120; former US 50 west; I-5 exit 461
MantecaR1.331CYosemite AvenueSigned as exit 1 eastbound
R2.302McKinley Avenue[41]
R3.323Airport Way (CR J3) – Sharpe Depot
R4.314Union RoadDiverging diamond interchange: first one constructed in California and opened to traffic on November 25, 2020[11]
R5.315South Main Street
T6.87
5.82[N 1]		6
 SR 99 south – Modesto, Fresno, Los Angeles		West end of SR 99 overlap; SR 99 exit 241
6.65[N 1]
6.20		East end of freeway on SR 99

 SR 99 north / Yosemite Avenue – Sacramento, Central Manteca		Interchange; east end of SR 99 overlap; SR 99 exit 242
8.84 CR J5 (Jack Tone Road)
​11.64French Camp Road
Escalon​
 CR J6 / CR J7 north (Escalon-Bellota Road, McHenry Avenue) – Farmington, Modesto		West end of CR J7 overlap
R16.92
 CR J7 south (Main Street) / Kern Street		East end of CR J7 overlap
Stanislaus
STA 0.00-T18.17		​3.16
 CR J9 north (Valley Home Road) – Valley Home		West end of CR J9 overlap
​​
 CR J14 north (Twenty-Six Mile Road)		West end of CR J14 overlap
Oakdale5.12

 SR 108 west (F Street) / CR J9 / CR J14 south (Yosemite Avenue) – Modesto		West end of SR 108 overlap; east end of CR J9 / CR J14 overlap
Tuolumne
TUO R0.00-R41.52		​8.19 CR J59 (La Grange Road) – La Grange, MercedNorthern terminus of CR J59
​​ CR E15 (O'Byrnes Ferry Road) – CopperopolisSouthern terminus of CR E15
​12.08
 SR 108 east – Sonora		East end of SR 108 overlap
Chinese Camp15.52
 SR 49 north – Sonora		West end of SR 49 overlap
Tuolumne River / Don Pedro ReservoirR19.61James E. Roberts Bridge
​R23.90
 SR 49 south – Coulterville, Mariposa		East end of SR 49 overlap
Buck MeadowsR39.46
 CR J132 (Smith Station Road, Greeley Hill Road) to SR 132 – Coulterville, Merced		Eastern terminus of CR J132
Yosemite National Park East end of state maintenance at western park boundary
​Big Oak Flat Entrance Station; park fee or pass required for entry[17]
Mariposa
MPA R41.52-43.75		​

 Big Oak Flat Road to SR 41 / SR 140 – Yosemite Valley
​Tuolumne Grove
(winter closure gate near the eastern end of the grove)[2][42]
Tuolumne
TUO 43.75-R56.15		​Tioga Pass Entrance Station (closed in winters); park fee or pass required for entry[17]
​West end of state maintenance at eastern park boundary
Mono
MNO R0.00-58.99		​R8.54Westbound winter closure gate
Lee ViningR12.06
50.74[N 2]
 US 395 north / Airport Road – Reno		West end of US 395 overlap
June Lake Loop North Junction46.40[N 2]
 SR 158 south – June Lake		Northern terminus of SR 158
Mono Mills Junction45.96[N 2]
13.37
 US 395 south – Bishop		East end of US 395 overlap
​18.49Eastbound winter closure gate
​39.05Westbound winter closure gate
​51.86
 Benton Crossing Road to US 395 – Owens River, Crowley Lake
Benton58.99 US 6 – Tonopah, BishopEast end of SR 120
1.000 mi = 1.609 km; 1.000 km = 0.621 mi
  1. ^ a b Indicates that the postmile represents the distance along SR 99 rather than SR 120.
  2. ^ a b c Indicates that the postmile represents the distance along US 395 rather than SR 120.

See also

References

  1. ^ a b c "State Truck Route List". California Department of Transportation. Retrieved February 9, 2026.
  2. ^ a b c d "Yosemite National Park Winter Road Closures". National Park Service. Retrieved January 29, 2023.
  3. ^ a b Staff. "Tioga Road/Big Oak Flat Road". America's Byways. Federal Highway Administration. Archived from the original on November 20, 2011. Retrieved November 29, 2011.
  4. ^ "Section 420". California Streets and Highways Code. Sacramento: California Office of Legislative Counsel. Retrieved February 25, 2026.
  5. ^ "Article 2 of Chapter 2 of Division 1". California Streets and Highways Code. Sacramento: California Office of Legislative Counsel. Retrieved February 6, 2019.
  6. ^ Federal Highway Administration (March 25, 2015). National Highway System: California (North) (PDF) (Map). Scale not given. Washington, DC: Federal Highway Administration. Retrieved September 30, 2017.
  7. ^ Natzke, Stefan; Neathery, Mike & Adderly, Kevin (June 20, 2012). "What is the National Highway System?". National Highway System. Washington, DC: Federal Highway Administration. Retrieved July 1, 2012.
  8. ^ "Article 2.5 of Chapter 2 of Division 1". California Streets & Highways Code. Sacramento: California Office of Legislative Counsel. Retrieved February 6, 2019.
  9. ^ California Department of Transportation (August 2019). "Officially Designated State Scenic Highways and Historic Parkways" (XLSX). Sacramento: California Department of Transportation. Retrieved September 30, 2017.
  10. ^ a b c "California Highways: Route 120". cahighways.org. Retrieved February 9, 2026.
  11. ^ a b c "State Route 120 / Union Road Interchange Project". City of Manteca. Retrieved February 14, 2024.
  12. ^ "Chinese Camp". California Office of Historic Preservation. Retrieved February 9, 2026.
  13. ^ "James E. Roberts Memorial Bridge". The Historical Marker Database. Retrieved February 9, 2026.
  14. ^ "Priest Grade, Grizzly Gulch". Pine Mountain Lake Association. Retrieved June 6, 2013.{{cite web}}: CS1 maint: deprecated archival service (link)
  15. ^ "CA-120 E". Google, Inc. Retrieved June 6, 2013.
  16. ^ "Groveland: South of the River". Tuolumne County Historical Society. Retrieved February 9, 2026.
  17. ^ a b c d "Yosemite National Park Fees & Passes". National Park Service. Retrieved December 31, 2021.
  18. ^ "Crane Flat Area". National Park Service. Retrieved February 9, 2026.
  19. ^ "The Tioga Road; a History 1883–1961 (1961, 1980), "Reconstruction," by Keith A. Trexler". yosemite.ca.us.
  20. ^ "Good Things to Know About Tioga Road in Summer". Yosemite Conservancy. Retrieved February 9, 2026.
  21. ^ "Tioga Pass". Encyclopaedia Britannica. Retrieved February 9, 2026.
  22. ^ "The Tioga Pass Road Historical Marker". The Historical Marker Database. Retrieved March 6, 2021.
  23. ^ Staff. "Lee Vining Canyon Scenic Byway". America's Byways. Federal Highway Administration. Archived from the original on October 23, 2011. Retrieved October 23, 2011.
  24. ^ "Floodgap Roadgap's Summer of 6 -- U.S. Highway 6, Part 1: US 6 in California". floodgap.com.
  25. ^ "BLM Granite Mountain Wilderness". Archived from the original on August 28, 2016. Retrieved August 27, 2016.
  26. ^ "Winter Driving Tips". Caltrans. Retrieved January 2, 2023.
  27. ^ "Groveland: South of the River". Tuolumne County Historical Society. Retrieved February 9, 2026.
  28. ^ "Big Oak Flat Road – Yosemite National Park CA". Living New Deal. Retrieved February 9, 2026.
  29. ^ "The Tioga Pass Road Historical Marker". The Historical Marker Database. Retrieved March 6, 2021.
  30. ^ Statutes 1921 p. 1627: State highway in San Joaquin County
  31. ^ California Department of Transportation, State Highway Routes: Selected Information Archived March 16, 2007, at the Wayback Machine, 1994 with 1995 revisions
  32. ^ Dennis, T.H. (August 1934). "State Routes Will Be Numbered and Marked with Distinctive Bear Signs". California Highways and Public Works. 11 (8): 20–21, 32. ISSN 0008-1159 – via Archive.org.
  33. ^ H.M. Gousha Company, California Archived October 13, 2007, at the Wayback Machine, 1942
  34. ^ American Association of State Highway Officials, log of U.S. Highways, American Highways, ca. 1932
  35. ^ "Tioga Road (HAER No. CA-149)". Historic American Engineering Record, National Park Service, U.S. Dept. of the Interior. Retrieved October 8, 2024.
  36. ^ "Big Oak Flat Road – Yosemite National Park CA". Living New Deal. Retrieved February 9, 2026.
  37. ^ California Department of Transportation (July 2007). "Log of Bridges on State Highways". Sacramento: California Department of Transportation.
  38. ^ California Department of Transportation, All Traffic Volumes on CSHS, 2005 and 2006
  39. ^ California Department of Transportation. "State Truck Route List". Sacramento: California Department of Transportation. Archived from the original (XLS file) on September 5, 2015. Retrieved June 30, 2015.
  40. ^ California Department of Transportation, California Numbered Exit Uniform System, SR-120 Eastbound and SR-120 Westbound, accessed February 2008
  41. ^ Wyatt, Dennis. "McKinley Interchange is Manteca Game Changer". Manteca/Ripon Bulletin. Retrieved January 6, 2024.
  42. ^ "View of eastbound Tioga Road at the open winter closure gate east of Tuolumne Grove". Google Street View. October 2018. Retrieved January 2, 2023.
  • Map: "Stanislaus National Forest, California," U.S. Forest Service, 1979.
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