[15] A written agreement was signed on December 13, 1851, forming a township, nine square miles of land were deeded to William McDaniel for $3,000, and the original city plans were laid out from that.

[19] Vacaville is surrounded by the Vaca Mountains to the south and to the west and the Sacramento Valley to the north and to the east.

Endangered plants, which have historically occurred in the vernal pool areas in and around Vacaville include Legenre limosa, Plagiobothrys hystriculus, Downingia humilis, Contra Costa goldfields (Lasthenia conjugens), and showy Indian clover (Trifolium amoenum).

According to the United States Census Bureau, the city has a total area of 28.6 square miles (74 km2), of which 0.74% is covered by water.

Excluding the Putah South Canal and minor local creeks, the only significant body of water within the city is the 105-acre (0.42 km2) Lagoon Valley Lake.

The unincorporated communities of Allendale and Elmira are generally considered to be part of "greater" Vacaville.

Vacaville has a typical Mediterranean climate (Köppen Csa) with hot, dry summers and cool, wet winters.

[11] The American Community Survey estimated the population identified as 50.5% non-Hispanic White, 24.8% Hispanic or Latino, 10.1% Black or African-American, 8.1% of two or more races, 7.8% Asian, 0.9% native Hawaiian or other Pacific Islander, and 0.7% American Indian or Alaska Native.

Hispanics or Latinos of any race were 22.9% of the population (17.0% of Mexican, 0.9% Puerto Rican, 0.5% Salvadoran, 0.3% Nicaraguan, 0.2% Guatemalan, and 0.2% Peruvian descent).

[31] Biotechnology/pharmaceutical facilities are operated by Genentech, ALZA Corporation, Kaiser Permanente, and Novartis International AG.

On June 1, 2023, Roche announced that it was looking to sell its 800-employee drug manufacturing plant in Vacaville, California, or shut down the factory by 2029.

[33] According to the city's 2021 Comprehensive Annual Financial Report,[34] the top employers in Vacaville (excluding government agencies) are: Public agencies also constitute major employers; however, the city does not include them in its financial reports because they do not collect employee information through the business license renewal process.

Between 1992 and 1995, local artist Guillermo Wagner Granizo installed 20 outdoor ceramic-tile murals, set into three freestanding walls near City Hall, entitled, "Vacaville Centennial".

[35][14] The murals depict various aspects of the history of the city of Vacaville, including the early pioneers Juan Manuel Vaca, Juan Felipe Peña, and William McDaniel, the early fruit industry, the first schools, Peña Adobe Park, the Nut Tree (a 1920s roadside fruit and nut stand), various parades, the annual tree lighting ceremony, "Hamburger Hill", and the factory outlet stores, among others.

The Vacaville Cultural Center, located at the southeast corner of Allison Drive and Ulatis Drive, houses a regional library, the Vacaville Performing Arts Theatre, an outdoor garden, and rentable event space.

The Vacaville Town Square Library is located within downtown, north of Main Street and east of Dobbins Road.

The Vacaville Art Gallery, located north of Andrews Park along East Monte Vista Avenue, provides exhibitions for local artists and community members.

[36] The city holds an annual Vacaville Fiesta Days celebration downtown, including a parade that features the public-school marching bands, gymnasts, and an electric car showcase, among other things.

[37] Other sites for tourists include the Vacaville Premium Outlets and the Nut Tree, which is home to a train for children, a carousel, and a life-size chessboard, as well as numerous stores and dining establishments.

Every Friday during the summer, the city holds the CreekWalk Concert Series in downtown Vacaville.

As of September 2022, there were 58,240 registered voters in Vacaville; of these, 22,198 (38.1%) are Democrats, 17,873 (30.7%) are Republicans, and 12,959 (22.3%) stated no party preference.

The Vacaville campus, located along North Village Parkway, features a 70-seat lecture hall, classrooms, science and computer laboratories, and a multipurpose room for theater arts and physical education.

SolanoExpress, which is operated by SolTrans, provides intercity connections to Fairfield, Benicia, Davis, Walnut Creek BART, and Sacramento.

The Nut Tree Airport is located in Vacaville and is operated by the Solano County General Services Department.