California State Route 29

State Route 29
State Route 29
	SR 29 highlighted in red
Route information
	Maintained by Caltrans
Length	105.648 mi (170.024 km)
Existed	1934–present
Major junctions
South end	I-80 in Vallejo
	SR 12 in Napa; SR 121 in Napa; SR 128 from Rutherford to Calistoga; SR 175 in Middletown; SR 53 in Lower Lake; SR 281 near Glenview; SR 175 from near Kelseyville to near Lakeport;
North end	SR 20 at Upper Lake
Location
Country	United States
State	California
Counties	Solano, Napa, Lake
Highway system
	State highways in California; Interstate; US; State; Scenic; History; Pre‑1964; Unconstructed; Deleted; Freeways;

State Route 29 (SR 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.

Route description

SR 29 begins at Interstate 80 (I-80) just north of the Carquinez Bridge in Vallejo. After running through the downtown area of Vallejo, it travels as a four-lane expressway (on some segments, five) through American Canyon to Napa. It then briefly becomes a freeway as it passes through Napa.

The expressway continues through the southern Napa Valley before terminating in Yountville. SR 29 continues as a 2-lane road through the Napa Valley cities of Oakville, Rutherford, St. Helena, and Calistoga, while also passing many of the region's notable vineyards and wineries. This portion of the highway is often heavily congested with rental cars and tour buses in spring and summer, when tourists flock to Napa Valley.

North of Calistoga, SR 29 climbs Mount Saint Helena, an extinct volcano, at the border between Napa County and Lake County. The road then heads north to Middletown and Lower Lake before going around the southern and western sides of Clear Lake, the largest natural freshwater lake completely within California. In Lakeport, SR 29 becomes a freeway as it bypasses the city. It then reverts as a two-lane highway before it terminates at Route 20 in Upper Lake.

Points of interest along Route 29 include Bothe-Napa Valley State Park, Bale Grist Mill State Historic Park, Robert Louis Stevenson State Park, the St. Helena Toll Road and Bull Trail, the Stone House, and the Lower Lake Stone Jail.

SR 29 is part of the California Freeway and Expressway System south of the intersection of Oak Knoll Avenue (approximately 1 mile north of the Napa city limits),^[2] and south of Yountville and north of SR 53 is 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 29 is eligible for inclusion in the State Scenic Highway System,^[5] but it is not officially designated as a scenic highway by the California Department of Transportation.^[6]

History

Historically, the route between the Napa Valley and Middletown was served by the Old Bull Trail Road, built by volunteers in the 1850s, that had grades of up to 35 percent. In 1868, this was replaced by the St. Helena Toll Road, which had more manageable inclines of up to 12 percent. The State of California purchased the toll road in 1925.

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).^[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 ^[1]^[7]^[8]	Exit ^[9]	Destinations	Notes
Solano SOL 0.00-5.96	Vallejo	0.00		I-80 west / Maritime Academy Drive – California Maritime Academy	Interchange; south end of SR 29; I-80 exit 29A
		1.01		Lemon Street to I-780
				Curtola Parkway to I-780
		2.07		Maine Street	Former SR 141
		4.73		SR 37 to I-80 – San Rafael, Sacramento, San Francisco	Interchange; SR 37 exit 19
Napa NAP 0.00-48.58	American Canyon	R2.77		Watson Lane, Green Island Road	Interchange
		4.71		SR 12 east (Jameson Canyon Road) / Airport Boulevard – Fairfield, Sacramento, Napa County Airport	South end of SR 12 overlap
		R6.20		SR 221 (Napa-Vallejo Highway) / Soscol Ferry Road – Downtown Napa, Lake Berryessa	Southern terminus of SR 221; at-grade intersection being converted to a double roundabout interchange that is scheduled to be open for traffic in fall 2024;^[10]^[11] SR 221 temporarily accessible as a northbound only interchange; Soscol Ferry Road accessible as a southbound only interchange
	Napa	R8.66		SR 121 south / SR 12 west (Carneros Highway) – Sonoma	North end of SR 12 overlap; south end of SR 121 overlap
			South end of freeway
	Napa	10.31	16	SR 121 north (Imola Avenue) – Lake Berryessa	North end of SR 121 overlap
		11.55	18A	First Street – Downtown Napa
		12.04	18B	Lincoln Avenue
		13.06	19	Trancas Street, Redwood Road	Former SR 221
			North end of freeway
				Sierra Avenue	Interchange; northbound exit and entrance
	Yountville	19.03		California Drive – Yountville, Veterans Home	Interchange
	Rutherford	24.60		SR 128 east (Rutherford Road) – Lake Berryessa, Winters	South end of SR 128 overlap
	Calistoga	36.89		SR 128 west (Foothill Boulevard) – Geyserville	North end of SR 128 overlap
Lake LAK 0.00-52.54	Middletown	5.81		SR 175 (Main Street) – Cobb Mountain Area	Eastern terminus of SR 175
	Lower Lake	20.31		SR 53 north / Morgan Valley Road (Main Street) – Clearlake, Business District	Southern terminus of SR 53
		27.89		SR 281 (Soda Bay Road) / Red Hills Road – Konocti Harbor, Soda Bay	Eastern terminus of SR 281
		31.05		SR 175 east – Middletown, Cobb Mountain Area	South end of SR 175 overlap
		R40.14		SR 175 west / South Main Street (SR 29 Bus. north), Soda Bay Road – Hopland	North end of SR 175 overlap
			South end of freeway
	Lakeport	R41.42	102	Lakeport Boulevard, Todd Road – Lakeport
	Lakeport	R42.68	103	11th Street, Scotts Valley Road – Lakeport
	North Lakeport	R45.15	106	Hill Road, Park Way
	North Lakeport	R47.85	108	Nice-Lucerne Cutoff (SR 29 Bus. south)
			North end of freeway
	Upper Lake	52.54		SR 20 to US 101 – North Shore Resorts, Williams	North end of SR 29
1.000 mi = 1.609 km; 1.000 km = 0.621 mi Concurrency terminus Incomplete access

References

^ ^a ^b ^c 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.
^ "Article 2 of Chapter 2 of Division 1". California Streets and Highways Code. Sacramento: California Office of Legislative Counsel. Retrieved February 6, 2019.
^ Federal Highway Administration (March 25, 2015). National Highway System: California (North) (PDF) (Map). Scale not given. Washington, DC: Federal Highway Administration. Retrieved October 18, 2017.
^ 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.
^ "Article 2.5 of Chapter 2 of Division 1". California Streets & Highways Code. Sacramento: California Office of Legislative Counsel. Retrieved February 6, 2019.
^ California Department of Transportation (August 2019). "Officially Designated State Scenic Highways and Historic Parkways" (XLSX). Sacramento: California Department of Transportation. Retrieved October 18, 2017.
^ California Department of Transportation (July 2007). "Log of Bridges on State Highways". Sacramento: California Department of Transportation.
^ California Department of Transportation, All Traffic Volumes on CSHS, 2005 and 2006
^ California Department of Transportation, California Numbered Exit Uniform System, State Route 29 Freeway Interchanges, Retrieved on 2009-02-05.
^ "Soscol Junction". California Department of Transportation. Retrieved March 29, 2023.
^ Eberling, Barry (July 9, 2022). "Here comes Soscol Junction, Napa County's biggest road project in years". Napa Valley Journal. Retrieved March 29, 2023.