260 mi · 5,500 ft of climbing · high point 2,618 ft · start/finish downtown Napa (First St & Main St)
Ridden Mar 24, 2026 · Foothills
The ride
Out over the Napa–Vallejo Highway and Jameson Canyon to I-80, through Fairfield, Vacaville, Dixon and Davis, then over to Highway 50 and up through Rancho Cordova, Folsom and Cameron Park to Placerville.
In Placerville you leave the highway and head north on Union Ridge Road, and Mosquito Road takes you down into the South Fork American River canyon. It's tight, steep and twisty, with the canyon dropping away below you, down to the Mosquito bridge over the river and back up the other side. It's a short stretch, but it's the reason the ride exists.
Home is the scenic way, not the freeway: back to 50, then Prairie City Road, Grant Line Road and Dillard Road across the farm country southeast of Sacramento, Twin Cities Road out to River Road at Walnut Grove, then CA-12 past Rio Vista and Suisun City, and Green Valley Road to Napa. About 260 mi with ~5,500 ft of climbing and a 2,618 ft high point, a comfortable day. Fuel's easy, Placerville is right there before the canyon. Mosquito Road is narrow, steep and slow in the canyon, so check for closures or roadwork before you go.
[Steve: add your full write-up here]
Key roads and highlights
Napa–Vallejo Highway, Jameson Canyon, I-80
US-50 through Folsom and Cameron Park to Placerville
Union Ridge Road
Mosquito Road down the South Fork American River canyon
Mosquito bridge
Prairie City Road and Grant Line Road
Dillard Road and Twin Cities Road
River Road / Victory Highway through Walnut Grove
CA-12 past Rio Vista and Suisun City
Green Valley Road home
Gallery
Ride photos coming soon
Not starting in Napa? No problem. Every Two Wheel Touring GPX is a loop that begins and ends at First & Main in downtown Napa, but you don't have to. Join the line wherever it's closest to you, ride any section you like, or flip the whole thing and run it the other way. For step-by-step help in Garmin, REVER, Calimoto, Scenic, Google My Maps, and a free GPX editor, see Riding a route from your own start.
Want just this one? Buy this route, $4
Or get every route we ride with Ride Files, $9/month or $50/year. Cancel anytime. Join Ride Files