Contra Costa County is a county located in the U.S. state of California, in the East Bay of the San Francisco Bay Area. As of the 2020 United States Census, the population was 1,165,927. The county seat is Martinez. It occupies the northern portion of the East Bay region of the San Francisco Bay Area and is primarily suburban. The county's name refers to its position on the other side of the bay from San Francisco. Contra Costa County is included in the San Francisco–Oakland–Berkeley, CA Metropolitan Statistical Area.
Bay Point, formerly West Pittsburg and originally Bella Vista is a census-designated place located in the East Bay region of the San Francisco Bay Area in Contra Costa County, California. Bay Point is just west of Pittsburg, California, and northeast of Concord, California, on the southern shore of Suisun Bay. The population of Bay Point was 21,349 as of 2010. The Pittsburg/Bay Point Station of the Bay Area Rapid Transit (BART) rail system is located adjacent to Bay Point in Pittsburg. The community is traversed by a freeway, State Route 4, the California Delta Highway. Being unincorporated, Bay Point does not have its own police department. The community is policed by the California Highway Patrol and the Contra Costa County Sheriff's Office. The ZIP code is 94565, and the area code is 925.
Concord is the largest city in Contra Costa County, California. According to an estimate completed by the United States Census Bureau, the city had a population of 129,295 in 2019 making it the eighth largest city in the San Francisco Bay Area. Founded in 1869 as Todos Santos by Don Salvio Pacheco II, a noted Californio ranchero, the name was later changed to Concord. The city is a major regional suburban East Bay center within the San Francisco Bay Area, and is 29 miles east of San Francisco.
Hercules is a city in western Contra Costa County, California. Situated along the coast of San Pablo Bay, it is located in the eastern region of the San Francisco Bay Area, about 10 miles (16 km) north of Berkeley, California. As of 2010, its population was 24,060, according to the United States Census Bureau. The site of Hercules was first developed in 1881 as a manufacturing facility of the California Powder Works for the production of its patented dynamite formulation, Hercules powder. In 1882, the Hercules Powder Company was incorporated and assumed responsibility for the Hercules site. It was one of several explosive manufacturers that were active along the Pinole shoreline in the late 19th to the mid-20th century. The small company town that grew up near the facility subsequently became known as "Hercules", and was incorporated at the end of 1900. Starting in the 1970s, Hercules was heavily redeveloped as suburban bedroom community that lies along the I-80 corridor in Western Contra Costa County. It has a very ethnically diverse population.
Martinez is a city and the county seat of Contra Costa County, California, in the East Bay region of the San Francisco Bay Area. Located on the southern shore of the Carquinez Strait, the city's population was 38,290 at the 2020 census. The city is named after Californio ranchero Ygnacio Martínez, having been founded on his Rancho El Pinole. Martinez is known for its historic center and its waterfront.
Pittsburg is a city in Contra Costa County, California, United States. It is an industrial suburb located on the southern shore of the Suisun Bay in the East Bay region of the San Francisco Bay Area, and is part of the Sacramento–San Joaquin River Delta area. The population was 76,416 at the 2020 United States Census.
The Port Chicago disaster was a deadly munitions explosion of the ship SS E. A. Bryan that occurred on July 17, 1944, at the Port Chicago Naval Magazine in Port Chicago, California, United States. Munitions detonated while being loaded onto a cargo vessel bound for the Pacific Theater of Operations, killing 320 sailors and civilians and injuring 390 others. Approximately two-thirds of the dead and injured were enlisted African American sailors.
Lamorinda is an area within Contra Costa County, California in the United States. The name is a portmanteau from the names of the three cities that make up the region: Lafayette, Moraga and Orinda.
The East Bay is the eastern region of the San Francisco Bay Area and includes cities along the eastern shores of the San Francisco Bay and San Pablo Bay. The region has grown to include inland communities in Alameda and Contra Costa counties. With a population of roughly 2.5 million in 2010, it is the most populous subregion in the Bay Area.
The Antioch–SFO + Millbrae line is a Bay Area Rapid Transit (BART) line in the San Francisco Bay Area that runs from Antioch station to San Francisco International Airport station (SFO), with some trains originating and terminating at Millbrae station. The line is colored yellow on maps, and BART sometimes calls it the Yellow Line. It serves 28 stations in Antioch, Pittsburg, Bay Point, Concord, Pleasant Hill, Walnut Creek, Lafayette, Orinda, Oakland, San Francisco, Daly City, Colma, South San Francisco, San Bruno, and Millbrae. It is the most-used BART line, and the only line with short turn trains to provide additional service.
State Route 242 is a three-mile (5 km) state highway in the U.S. state of California that links Interstate 680 north of Pleasant Hill to State Route 4 in Concord in Contra Costa County. Along with Interstate 580, State Route 24, Interstate 680 and State Route 4, it serves as the most direct route between the San Francisco Bay Area and the Sacramento–San Joaquin River Delta region.
Buchanan Field Airport is a public airport in Contra Costa County, California, United States, a mile west of the center of Concord and east of Pacheco. The airport's street address is 550 Sally Ride Drive, Concord.
The Port Chicago Naval Magazine National Memorial is a memorial dedicated in 1994 recognizing the dead of the Port Chicago disaster, and the critical role played by Port Chicago, California during World War II, in serving as the main facility for the Pacific Theater of Operations. The national memorial is located at the Concord Naval Weapons Station near Concord, California, in the United States.
Concord Naval Weapons Station was a military base established in 1942 north of the city of Concord, California at the shore of the Sacramento River where it widens into Suisun Bay. The station functioned as a World War II armament storage depot, supplying ships at Port Chicago. During World War II it also had a Naval Outlying Field at the southern edge of the base. It ceased being an operating airfield after World War II. During the Korean War, the Vietnam War and the Gulf War, Concord NWS processed and shipped thousands of tons of materiel out across the Pacific Ocean.
Seal Islands are a pair of islands in Suisun Bay at the mouth of the Sacramento-San Joaquin River Delta in Contra Costa County, California, 10 km east of Benicia, and 500 metres off-shore from the former Concord Naval Weapons Station and Port Chicago Naval Magazine.
The Giant Powder Company was an explosives manufacturing company which operated from the mid 19th century through the first half of the 20th century, located in the San Francisco Bay Area of California. The Giant Powder Company was the first company in the United States to produce dynamite under an exclusive license from Alfred Nobel.
The Walnut Creek mainstem is a 12.3-mile-long (19.8-kilometer) northward-flowing stream in northern California. The Walnut Creek watershed lies in central Contra Costa County, California and drains the west side of Mount Diablo and the east side of the East Bay Hills. The Walnut Creek mainstem is now mostly a concrete or earthen flood control channel until it reaches Pacheco Creek on its way to Suisun Bay. Walnut Creek was named for the abundant native Northern California walnut trees which lined its banks historically. The city of Walnut Creek, California was named for the creek when its post office was established in the 1860s.
Mallard Island is a small island in Suisun Bay, at the confluence of the Sacramento and San Joaquin rivers. It is part of Contra Costa County, California. Its coordinates are 38°02′31″N121°55′07″W, and the United States Geological Survey measured its elevation as 3 ft (0.91 m) in 1981. It appears in a 1953 USGS map of the area.
Middle Ground Island is an island in Suisun Bay, an embayment of San Francisco Bay, downstream of the Sacramento–San Joaquin River Delta. It is part of Solano County, California, and not managed by any reclamation district. Its coordinates are 38°03′46″N121°58′53″W, and the United States Geological Survey measured its elevation as 0 ft (0 m) in 1981.
