A portion of the South Campus at the University of California, Davis, is in Solano County.

At the request of General Mariano Guadalupe Vallejo, the county was named for Chief Solano of the Suisun people, a Native American tribe of the region and Vallejo's close ally.

"Solano" is a common surname in the north of Spain, especially in Navarra, Zaragoza, and La Rioja.

Between 2017 and 2023, California Forever purchased over 50,000 acres of land in the county for an estimated $900 million to develop a new city.

[15] Solano County has a number of rare and endangered species, including the Delta green ground beetle,[16] the wildflower Lasthenia conjugens, commonly known as Contra Costa goldfields,[17] and the annual plant Legenere limosa or false Venus' looking glass.

The following table includes the number of incidents reported and the rate per 1,000 persons for each type of offense (2011).

The County government provides countywide services such as elections and voter registration, law enforcement, jails, vital records, property records, tax collection, public health, and social services.

However, the northern area of Solano County including Vacaville and Dixon have begun shifting right as evidenced by the 2022 midterms, voters in Congressional District 4 favoring the Republican candidate 50.3% to 49.7%.

[39] Solano County is split between California's 4th, 7th and 8th congressional districts, represented by Mike Thompson (D–St.

[42] On November 4, 2008, Solano County voted 55.82% in favor of Proposition 8, which amended the California Constitution to ban same-sex marriages.

[44] According to the California Secretary of State, as of February 10, 2019, Solano County has 236,028 registered voters.

[45] Democrats hold voter-registration advantages in all incorporated cities and towns in Solano County.

However, Republicans lead in registration in the unincorporated communities of the county (40%-35%), making Solano the only county in the Bay Area where Republicans out-number Democrats in unincorporated communities.