Napa () is the largest city in and the county seat of Napa County, California. It is the principal city of the Napa County Metropolitan Statistical Area, with a population of 78,130 as of the 2019 United States census estimate. It is the second-largest city in California's Wine Country, after Santa Rosa. Napa was incorporated as a city in 1872.

Petaluma (; Coast Miwok: Péta Lúuma) is a city in Sonoma County, part of the North Bay sub-region of the San Francisco Bay Area, located 37 mi (60 km) north of San Francisco. Its population was 57,941 according to the 2010 Census.The Rancho Petaluma Adobe, located in Petaluma, is a National Historic Landmark. Construction began in 1836 by order of General Mariano Guadalupe Vallejo, who was then the Commandant of the San Francisco Presidio. It was the center of a 66,000-acre (270 km2) ranch stretching from Petaluma River to Sonoma Creek. The adobe is considered one of the best-preserved buildings of its era in Northern California. Other historical buildings include the Washoe House, built in 1859, and the Petaluma Creamery, established in 1903, which marked Petaluma as an agricultural center for eggs and dairy. The name comes from the Coast Miwok name Péta Lúuma (lit. 'hill backside'), a village once located near the present-day city borders. Petaluma has a well-preserved, historic city center which includes many buildings that survived the 1906 San Francisco earthquake.

Novato ( nə-VAH-toh) is a city in northern Marin County, in the North Bay region of the San Francisco Bay Area, in the U.S. state of California. At the 2010 census, its population was 51,904. Novato is located about 10 miles (16 km) northwest of San Rafael and about 30 miles (48 km) north of San Francisco on U.S. 101. Novato has been called one of the best places to live in the U.S.

Vallejo ( və-LAY-(h)oh; Spanish: [baˈʎexo]) is a waterfront city in Solano County, California, located in the North Bay subregion of the San Francisco Bay Area. Vallejo is geographically the closest North Bay city to the inner East Bay, so it is sometimes associated with that region. Its population was 115,942 at the 2010 census. It is the tenth most populous city in the San Francisco Bay Area, and the largest in Solano County. The city is named after Don Mariano Guadalupe Vallejo, the famed Californio general and statesman. He was a leading proponent of California's statehood and one of the first members of the California State Senate. The neighboring city of Benicia is named for his wife, Francisca Benicia Carrillo de Vallejo. Vallejo has twice served as the capital of the state of California: once in 1852 and again in 1853.Vallejo sits on the northeastern shore of San Pablo Bay, 30 mi (48 km) north of San Francisco, the northwestern shore of the Carquinez Strait and the southern end of the Napa River, 15 mi (24 km) south of Napa. Vallejo is home to the California Maritime Academy, Six Flags Discovery Kingdom theme park, the former Mare Island Naval Shipyard, and the regional office for Region 5 of the United States Forest Service.