California State Route 29

Route 29 in Vallejo

End of Route 29 at Route 20 in Upper Lake

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 highway then runs as a two-lane road through the Napa Valley cities and towns of Yountville, 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 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]

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.

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).[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 / Soscol Ferry Road – Downtown Napa, Lake Berryessa	Future roundabout interchange to begin construction in Fall 2021.
	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
	Lower Lake	20.31		SR 53 north / Morgan Valley Road (Main Street) – Clearlake, Business District
	​	27.89		SR 281 (Soda Bay Road) / Red Hills Road – Soda Bay
	​	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
		R42.68	103	11th Street, Scotts Valley Road – Lakeport
	North Lakeport	R45.15	106	Hill Road, Park Way
		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

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Wikimedia Commons has media related to California State Route 29.

• California @ AARoads - State Route 29
• Caltrans: Route 29 highway conditions
• California Highways: SR 29
• Cal-NExUS: Route 29 North
• Cal-NExUS: Route 29 South