Sister cities of Vallejo, California

Vallejo (/vəˈleɪ.oʊ/ or /vəˈleɪhoʊ/; Spanish: [baˈʎexo]) is the largest city in Solano County, California, United States. The population was 115,942 at the 2010 census. It is the tenth most populous city in the San Francisco Bay Area, and is located on the northeastern shore of San Pablo Bay. Vallejo is named for General Mariano Guadalupe Vallejo (the neighboring city of Benicia is named for his wife).

Vallejo is home to the Six Flags Discovery Kingdom theme park (formerly Marine World and Marine World Africa USA); the now-defunct Mare Island Naval Shipyard; the regional office for Region 5 of the United States Forest Service; the California Maritime Academy (part of the California State University system); the Vallejo Center campus of Solano Community College; and Touro University California, a graduate school offering programs in osteopathic medicine, education, pharmacy, physician assistant studies, and public health. Ferry service runs from a terminal on Mare Island Strait to San Francisco, through the BayLink division of SolTrans.

Vallejo has twice served as the capital of the state of California: once in 1852 and again in 1853, both periods being brief. The State Capitol building burned to the ground in the 1880s and the Vallejo Fire Department requested aid from the Fire Department at Mare Island Naval Shipyard. As there were no bridges at that time, the Mare Island Fire Department had to be ferried across the Napa River, arriving to find only the foundation remaining. This was the first recorded mutual aid response in the state of California.

Some of the first Europeans drawn to the Vallejo area were attracted by the sulfur springs; in the year 1902 the area was named Blue Rock Springs.