Via the Golden Gate Bridge / Highway 101
Travel North on 101 to Novato. Take Hwy. 37 exit to Hwy. 121 to Napa/Sonoma. Continue on Hwy. 121 to Hwy. 29. Turn left onto Hwy. 29 and follow signs north to St. Helena. 

Via the Bay Bridge/Interstate 80
Travel east on I-80 to Vallejo. Take Hwy. 37 (Napa/Columbus Pkwy.) exit. Follow signs to Napa and continue on Hwy. 37 to Hwy. 29. Turn right onto Hwy. 29 and continue north through Napa Valley to St. Helena.