Contra Costa County

E17060

administrative division county

Contra Costa County is a populous county in the San Francisco Bay Area known for its suburban communities, regional parks, and role as a residential and industrial hub east of Oakland and San Francisco.

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All labels observed (11)

Label	Occurrences
Contra Costa County canonical	100
Contra Costa County, California	91
West Contra Costa County	7
East Contra Costa County	4
Contra Costa County government	3
Central Contra Costa County	1
Contra Costa County metropolitan area	1
Contra Costa County unincorporated area	1
Eastern Contra Costa County	1
Western Contra Costa County	1
western Contra Costa County	1

How this entity was disambiguated

This entity first appeared as the object of triple T22112 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.

NED1 Entity disambiguation (via context triple) gpt-5-mini-2025-08-07

Target entity: Contra Costa County
Context triple: [Northern California, contains, Contra Costa County]

A. Alameda County
Alameda County is a populous and diverse county in the San Francisco Bay Area that includes cities such as Oakland and Berkeley.
B. Sacramento County
Sacramento County is a county in Northern California that includes the state capital, Sacramento, and serves as a major political and economic hub of the region.
C. Santa Clara County
Santa Clara County is a populous and economically significant county in California’s Silicon Valley, home to major technology companies and cities such as San Jose.
D. San Francisco County
San Francisco County is a densely populated, culturally diverse urban county on the tip of the San Francisco Peninsula, encompassing the city of San Francisco and serving as a major economic and technological hub in California.
E. San Mateo County, California
San Mateo County, California is a coastal county in the San Francisco Bay Area known for its affluent communities, tech industry presence, and proximity to both San Francisco and Silicon Valley.
F. None of above. chosen
G. Unsure - the case is ambiguous/there is not enough information to decide.

NED2 Entity disambiguation (via description) gpt-5-mini-2025-08-07

Target entity: Contra Costa County
Target entity description: Contra Costa County is a populous county in the San Francisco Bay Area known for its suburban communities, regional parks, and role as a residential and industrial hub east of Oakland and San Francisco.

A. Alameda County
Alameda County is a populous and diverse county in the San Francisco Bay Area that includes cities such as Oakland and Berkeley.
B. Sacramento County
Sacramento County is a county in Northern California that includes the state capital, Sacramento, and serves as a major political and economic hub of the region.
C. Santa Clara County
Santa Clara County is a populous and economically significant county in California’s Silicon Valley, home to major technology companies and cities such as San Jose.
D. San Francisco County
San Francisco County is a densely populated, culturally diverse urban county on the tip of the San Francisco Peninsula, encompassing the city of San Francisco and serving as a major economic and technological hub in California.
E. San Mateo County, California
San Mateo County, California is a coastal county in the San Francisco Bay Area known for its affluent communities, tech industry presence, and proximity to both San Francisco and Silicon Valley.
F. None of above. chosen

Statements (93)

Predicate	Object
instanceOf	administrative division ⓘ county ⓘ
borders	Alameda County ⓘ Napa County ⓘ Sacramento County ⓘ San Joaquin County ⓘ Solano County ⓘ Sonoma County, California ⓘ surface form: Sonoma County
bordersBodyOfWater	Carquinez Pass ⓘ surface form: Carquinez Strait San Francisco Bay ⓘ San Pablo Bay ⓘ Suisun Bay ⓘ
country	United States of America ⓘ
hasCharacteristic	commuter region ⓘ populous ⓘ regional parks network ⓘ suburban ⓘ
hasCountySeat	Martinez, California ⓘ
hasEconomicSector	industrial ⓘ residential ⓘ retail ⓘ services ⓘ
hasMajorBridge	Benicia–Martinez Bridge ⓘ Carquinez Bridge ⓘ Richmond–San Rafael Bridge ⓘ
hasMajorCity	Alamo, California ⓘ Antioch, California ⓘ Bay Point, California ⓘ Bayview, Contra Costa County, California ⓘ Bayview-Montalvin, California ⓘ Bethel Island, California ⓘ Blackhawk, California ⓘ Brentwood, California ⓘ Camino Tassajara, California ⓘ Castle Hill, California ⓘ Clayton, California ⓘ Clyde, California ⓘ Concord, California, United States ⓘ surface form: Concord, California Crockett, California ⓘ Danville, California ⓘ Diablo, California ⓘ Discovery Bay, California ⓘ Richmond, California ⓘ surface form: East Richmond Heights, California El Cerrito, California, United States ⓘ surface form: El Cerrito, California El Sobrante, California ⓘ Hercules, California ⓘ Kensington, California ⓘ Blackhawk, California ⓘ surface form: Knightsen, California Lafayette, California, United States ⓘ surface form: Lafayette, California Marina Bay, Richmond, California ⓘ Vine Hill, California ⓘ surface form: Montalvin Manor, California Moraga, California ⓘ Mountain View, Contra Costa County, California ⓘ Norris Canyon, California ⓘ Richmond, California ⓘ surface form: North Richmond, California Oakley, California ⓘ Orinda, California ⓘ Pacheco, California ⓘ Pinole, California ⓘ Pittsburg, California ⓘ Pleasant Hill, California ⓘ Port Costa, California ⓘ Norris Canyon, California ⓘ surface form: Reliez Valley, California Richmond, California ⓘ Rodeo, California ⓘ Vine Hill, California ⓘ surface form: Rollingwood, California San Miguel, Contra Costa County, California ⓘ San Ramon, California ⓘ Pacheco, California ⓘ surface form: Saranap, California Vine Hill, California ⓘ surface form: Shell Ridge, California Tara Hills, California ⓘ Vine Hill, California ⓘ Walnut Creek, California ⓘ
hasMajorHighway	Interstate 680 ⓘ Interstate 80 ⓘ State Route 24 ⓘ State Route 242 ⓘ State Route 4 ⓘ
hasRegionalPark	Black Diamond Mines Regional Preserve ⓘ Briones Regional Park ⓘ Carquinez Strait Regional Shoreline ⓘ Contra Loma Regional Park ⓘ Del Valle Regional Park ⓘ Las Trampas Regional Wilderness ⓘ Mount Diablo State Park ⓘ Point Pinole Regional Shoreline ⓘ
locatedEastOf	Oakland ⓘ surface form: Oakland, California San Francisco ⓘ
locatedIn	California, United States ⓘ surface form: California San Francisco Bay Area ⓘ
locatedInTimeZone	Pacific Time Zone ⓘ
partOfRegion	East Bay ⓘ
servedByTransitSystem	BART ⓘ surface form: Bay Area Rapid Transit