This is wine country in its quieter, older form, with small family vineyards on the lower slopes, oak savanna on the hills and old stone wineries, and it is far less crowded than neighbouring Napa. Sonoma itself, the historic town at the southern end, has a Spanish plaza, an old mission and an easy, unhurried feel.
The valley has a rich history. The Sonoma Mission, founded in 1823, was the last and northernmost of California's Spanish missions, and in 1846 a band of American settlers raised the Bear Flag at the plaza and declared a short-lived republic, a rebellion that became part of the story of California's annexation. Agoston Haraszthy, a Hungarian émigré, planted the Buena Vista vineyard here in the 1850s and is often called the father of California wine. Further up, Jack London bought a ranch at Glen Ellen in 1905, and his Beauty Ranch is now a state park, with his stone house ruins and his grave on a wooded knoll.
The riding is pleasant rather than thrilling. Highway 12 runs the length of the valley, with vineyards on either side and the hills glowing gold in summer, and side roads such as Bennett Valley Road and Sonoma Mountain Road wind up into the oaks, narrow, rough and beautiful. Traffic on Highway 12 is heavy at weekends and during harvest, and cyclists share the quieter lanes. The morning light, the smell of crushed grapes in autumn and the stillness of the hills make it a delight.
Fuel and food are in Sonoma and Santa Rosa, and the plaza has plenty of cafés, bakeries and a picnic-friendly lawn. Spring is green and full of wildflowers, summer is hot and dry, and autumn brings the vintage and bright yellow vine leaves. Winter is wet but quiet. Pick a weekday if you can, and leave time to wander the plaza, where an old mission building and a few adobe walls give a hint of the valley's past.