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Take the Napa County highway trivia quiz

From the Series: Traffic Tales of Napa County series
Boulderscape (copy)

Employees from Boulderscape add rock-like texture to the Highway 12/Jameson Canyon retaining wall in 2014. Caltrans that year was busy widening this busy link between Solano and Napa counties from two lanes to four lanes.

Napa County has six highways and freeways running through it—or is it seven?

The answer to this seemingly straightforward question isn’t quite clear. Here’s a trivia – but hopefully not trivial – look at the county’s main roads.

What is the shortest stretch of highway or freeway within the county? This ends up being a trick question. Some maps show about 1,000 feet of Highway 37 passing through Napa County, others show it staying in Sonoma and Solano counties.

Napa County Public Works Director Steven Lederer said he think Highway 37 does enter Napa County, but it’s hard to tell. Planning, Building and Environmental Services Director David Morrison said Google Earth shows a segment might be in Napa County, though he’s inclined to say “no.” County Assessor John Tuteur said “no.”

Take away the Highway 37 conundrum and the answer is Interstate 80. The southeast corner of the county takes in a mile of the freeway between Vallejo and Fairfield.

What is Napa County’s longest stretch of highway or freeway?

Highway 29, the Napa Valley’s main drag. It traverses the entire county north-to-south, from the remote, forested Lake County line near Mount St. Helena to bustling, congested American Canyon. That’s a distance of about 49 miles.

Highway 128 cutting west-to-east across the county is almost as long, at 46.5 miles. This highway enters the northern county from Sonoma County, runs down the Napa Valley sharing the Highway 29 route, cuts east on Rutherford Road, then heads past Lake Hennessey and Lake Berryessa to Solano County.

What are the six -or seven- highways and freeways stretches in Napa County? Highways 12, 29, 121, 128 and 221 and I-80 for sure, with Highway 37 a possibility.

When did the Jameson Canyon highway get built?

With automobiles becoming popular, the state in 1912 announced it would spend $18 million on a state highway system. Napa County wanted to be included.

California was securing local right-of-way in 1914. The cement highway would come westward from Sacramento through Fairfield, go through Jameson Canyon into Napa County, pass through the city of Napa, then cut west to Sonoma County and beyond.

A milestone came in November 1918.

“The new state highway south of Napa was thrown open to the public Monday,” the Weekly Calistogan reported. “This is a great boon to automobilists bound for Vallejo or Sacramento points, for it does away with the wide detour so long necessary out through Coombsville.”

In December, 1919, California completed the state highway section from the city of Napa to Stanly Lane heading toward Sonoma. Meanwhile, the county also worked on county highways, such as today’s Highway 29 route up Napa Valley.

What is the busiest Napa County highway/freeway?

No, it’s not Highway 29 in American Canyon, the city of Napa or the Upvalley – not by a long shot.

Highway 29 at its busiest point in Napa County – near First Street in the city of Napa – carries about 71,000 vehicles daily. That short stretch of I-80 in the south county carries around 145,000, according to Caltrans.

Does Napa County have a state scenic highway?

No. But the county has some contenders, should local officials ever want to the state to put up those scenic highway signs with the poppy.

California law passed in 1963 allowed for state scenic highways and listed eligible highways. Listed for Napa County are Highway 29 from Vallejo to the city of Napa, Highway 29 from the city of Napa to Lake County, Highway 221 and Silverado Trail (Highway 121) south of Trancas Street.

Last year, Assemblywoman Cecilia Aguiar-Curry, D-Winters, carried legislation that makes Highway 128 eligible.

But the state doesn’t impose scenic highway status on counties. Napa County has yet to apply and show its roads meet the criteria.

Barry Eberling's memorable stories from 2019

Here's some of my 2019 stories from the Napa County world of transportation, wine and communities - nothing too heavy, but hopefully with useful information.

You can reach Barry Eberling at 256-2253 or

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Napa County Reporter

Barry Eberling covers Napa County government, transportation, the environment and general assignments. He has worked for the Napa Valley Register since fall 2014 and previously worked 27 years for the Daily Republic of Fairfield.

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