U.S. Route 101
U.S. Route 101, or U.S. Highway 101 (US 101) is a north–south United States Numbered Highway that runs through the states of California, Oregon, and Washington, on the West Coast of the United States. It is also known as (The Royal Road) where its route along the southern and central California coast approximates the old trail which linked the Spanish missions, pueblos, and presidios. It merges at some points with California State Route 1 (SR 1).
Sonoma County, California
U.S. Route 101 is the westernmost Federal highway in the U.S.A. Running north/south through the states of California, Oregon, and Washington, it generally parallels the coastline from the Mexico–US border to the Canada–US border. Highway 101 links seven of the county's nine incorporated cities: Cloverdale, Healdsburg, Windsor, Santa Rosa, Rohnert Park, Cotati, and Petaluma. It is a freeway for almost its entire length within the county, except for a section south of Petaluma.