Contra Costa County, California

Clayton (formerly Clayton's and Claytonville) is a city in Contra Costa County, California, United States. The population was 11,585 as of the 2020 census.

Clayton Valley Charter High School (CVCHS) is a comprehensive charter high school located in Concord, California, United States, just under two miles from Clayton. Most of the school's students live in Clayton and the nearby Concord neighborhoods. As a charter school, CVCHS has both a traditional principal as site leader and an executive director who heads the school district central office as superintendent. It also has a nine-member governing board.CVCHS houses ClaytonArts Academy. It is the location of the local radio station 90.5 "The Edge" KVHS, which broadcasts mostly hard rock and heavy metal music. Its newspaper is The Talon, which is part of the High School National Ad Network. The current executive director is Dave Fehte.

Toyota Pavilion at Concord (formerly known as Concord Pavilion) is an amphitheatre located in Concord, California. It is owned by the City of Concord and operated by Live Nation. The Pavilion has a capacity of 12,500 people and opened in 1975 as the Concord Pavilion. It is used for concerts, local community events (including an annual jazz festival) and local high school graduations. The Pavilion was designed by architect Frank Gehry and landscape architect Peter Walker. Gehry also designed its mid-1990s renovations, which included more parking and seats. The venue has hosted numerous professional musical acts over the years of its operation and continues to do so to this day. Bing Crosby played his last US concert at the Pavilion on August 16, 1977. Lawrence Welk's appearance at the Concord Pavilion on June 13, 1982, was billed as his farewell performance. Legendary concert promoter Bill Graham was killed in a 1991 helicopter crash after leaving a concert at the Pavilion by Huey Lewis and the News, having just discussed with the band about organizing a benefit for the victims of that year's fire in the Oakland Hills; Graham's production company, Bill Graham Presents (BGP), had been the booking agent for the Concord Pavilion since at least 1985.In a deal with the city of Concord, Bill Graham Presents took over operations of the facility in February 2000. Shortly thereafter, its name was changed to the Chronicle Pavilion at Concord, following the purchase of the naming rights by the business agent of the San Francisco Chronicle, the San Francisco Newspaper Agency. BGP was purchased in 2000, along with its parent, SFX Promotions, by Clear Channel Communications; in 2005, Clear Channel would spin off its concert operations into Live Nation, which operates the Pavilion to this day. The Pavilion changed its name in April 2006, when it became the Sleep Train Pavilion after the California-based mattress retailer (now a Houston, Texas-based company) purchased the naming rights; by 2017 the retailer folded into Mattress Firm.In December 2013, as part of a 10-year contract renewal between Venue Nation (previously known as Live Nation) and the City of Concord, the Pavilion's name was changed again to the Concord Pavilion.On August 3, 2023, the Pavilion was renamed Toyota Pavilion at Concord after the local Northern California Toyota Dealers Association, which consists of 58 local Toyota dealers operating in the northern half of the state, purchased the naming rights. The First Battle of the Bands for high school, middle school, and elementary school students took place in 2006 and the winner was a high school band, Poster Boy.

The Concord Jazz Festival is an annual event that was established in 1969 in Concord, California. The festival was launched by Carl Jefferson, a car dealer and jazz enthusiast, who managed to get a group of friends to support the concept. The city agreed to pay for half the cost. The first festival was held on 26 January 1969 in an 8-acre park called the Concord Boulevard Neighborhood Park (later renamed Dave Brubeck Park), adjacent to Concord High School. It attracted 17,000 attendees. Performers in subsequent years included Oscar Peterson, Pearl Bailey, Peter Nero, George Shearing, Ella Fitzgerald, Gerry Mulligan, and Dave Brubeck. In May 1975 the Concord Pavilion was opened as a home for the festival. It is an amphitheater in the Concord hills, featuring a roofed area with no walls that covers 3,500 seats, plus room for 4,500 more on the surrounding lawns. The pavilion is used for many other purposes.Carl Jefferson founded Concord Records in 1973, with the Concord Jazz label. In 2004 the Concord Music Group was formed by the merger of Concord Records with Fantasy Records. The labels have released many classic albums.

Cowell is a former unincorporated community now annexed to Concord in Contra Costa County, California. It lies at an elevation of 259 feet (79 m). Cowell was named for Joshua Cowell, local landowner. A post office operated at Cowell from 1922 to 1969. Cowell was a company town for Cowell Portland Cement. Other than a former firehouse, nothing remains of the former town, which was replaced by the Walnut Country subdivision, more commonly known as "The Crossings," during the 1970s. A looming, dormant 244-foot high smokestack remained as the most prominent reminder of Cowell until it was demolished in 2009.

North Gate is a census-designated place in Contra Costa County, California. North Gate sits at an elevation of 253 feet (77 m). The 2010 United States census reported North Gate's population was 679.

California's 11th congressional district is a congressional district in the U.S. state of California and is represented by Nancy Pelosi. Before redistricting, the 11th district consisted of most of Contra Costa County. Mark DeSaulnier, a Democrat, represented the district from January 2015 to January 2023. Cities and CDPs in the district included Alamo, Bay Point, Blackhawk, Clayton, Concord, Diablo, El Cerrito, El Sobrante, Kensington, Lafayette, Moraga, Orinda, Pinole, Pittsburg, Pleasant Hill, San Pablo, Richmond, and Walnut Creek; most of Danville; and parts of Antioch and Martinez.Following redistricting in 2023 by the California Citizens Redistricting Commission, the 11th district is entirely in San Francisco, and includes most of the city with the exception of the Excelsior District, Visitacion Valley, Portola, and Ocean View on the city's southern edge. Former Speaker of the House Nancy Pelosi represents the new 11th district.

Area code 925 is a telephone area code in the North American Numbering Plan for a northern part of the U.S. state of California. It was created in an area code split of area code 510 in 1998. The numbering plan area comprises the inland portions of the East Bay counties of Alameda and Contra Costa.

Mount Diablo is a mountain of the Diablo Range, in Contra Costa County of the eastern San Francisco Bay Area in Northern California. It is south of Clayton and northeast of Danville. It is an isolated upthrust peak of 3,849 feet (1,173 meters), visible from most of the San Francisco Bay Area. Mount Diablo appears from many angles to be a double pyramid and has many subsidiary peaks. The largest and closest is North Peak, the other half of the double pyramid, which is nearly as high in elevation at 3,557 feet (1,084 m), and is about one mile (1.6 kilometers) northeast of the main summit. The mountain is within the boundaries of Mount Diablo State Park, which is administered by California State Parks.

The Mount Diablo meridian, established in 1851, is a principal meridian extending north and south from its initial point atop Mount Diablo in California at W 121° 54.845. Established under the U.S. Public Land Survey System, it is used to describe lands in most of northern California and all of Nevada. Mount Diablo also marks the baseline at latitude 37°52′54″N.

Concord High School is a 9-12 public high school in Concord, California, United States,. It is one of the six high schools in the Mount Diablo Unified School District. Concord High School was constructed in 1966 and currently provides 144,373 square feet (13,412.7 m2) in permanent structure, including about 70 classrooms, a library, and other structures. As of 2023, the current principal is Julene MacKinnon.

Castle Rock Regional Recreation Area is a 18,000 acres (73 km2) regional park of the East Bay Regional Park District. It is located in Contra Costa County, in the East Bay region of northern California.