Oakley is a city in Contra Costa County, California, United States.
 It is within the nine-county San Francisco Bay Area.
 The January 1, 2016 population was 40,144, as determined by the State Department of Finance.
 Oakley was incorporated in 1999 and is the most recently incorporated city in Contra Costa County.
 Oakley is part of the East Contra Costa Bicycle Plan, which has existing facilities in Oakley as well as plans for further expansion.
Concord ( ) is the largest city in Contra Costa County, California.
 At the 2010 census, the city had a population of 122,067 making it the 8th largest city in the San Francisco Bay Area.
 Founded in 1869 as the community of Todos Santos by Salvio Pacheco, the name was changed to Concord within months.
 The city is a major regional suburban East Bay center within the San Francisco Bay Area, and is 29 mi east of San Francisco.
Contra Costa Centre is a census-designated place in Contra Costa County, California.
 Contra Costa Centre sits at an elevation of 92 feet (28 m).
 The 2010 United States census reported Contra Costa Centre's population was 5,364.
 Contra Costa Centre is served by the Pleasant Hill / Contra Costa Centre BART station.
The Contra Costa Water District (CCWD) is an agency that was created in 1936 to supply water for consumers in eastern Contra Costa, California.
 It is now one of the largest water districts in California, serving about 500,000 people in Central and Eastern Contra Costa County.
The County Connection (officially, the Central Contra Costa Transit Authority, CCCTA) is a Concord-based public transit agency operating fixed-route bus and ADA paratransit (County Connection LINK) service in and around central Contra Costa County in the San Francisco Bay Area.
 Established in 1980 as a joint powers authority, CCCTA assumed control of public bus service within central Contra Costa first begun by Oakland-based AC Transit as it expanded into suburban Contra Costa County in the mid-1970s (especially after the opening of BART).
John Gioia (pronounced: Joy-a ) is an American politician.
 He has served on the Contra Costa County Board of Supervisors in Contra Costa County, California since 1998 and was overwhelmingly re-elected three times.
 He served as chair in 2002, 2006 and 2010.
 John Gioia is a Democrat.
 Contra Costa Supervisory seats are non-partisan.
State Route 242 (SR 242) is a short three-mile (5 km) connector route that links Interstate 680 north of Pleasant Hill to State Route 4 in Concord.
 In 2000, State Route 242 was widened to six through-traffic lanes for the entire route.
 Ramp metering is present at all onramps, and is used southbound in the morning and northbound in the evening.
 It was signed as part of State Route 24 until ca. 1987.
 Currently, 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 River Delta region of Northern California.
Tri Delta Transit, formally the Eastern Contra Costa Transit Authority, is a joint powers agency of the governments of Pittsburg, Antioch, Oakley, Brentwood, and Contra Costa County that provides bus service for the eastern area of Contra Costa County, California, United States.
 Tri Delta Transit local buses connect to the BART rapid transit system at Pittsburg/Bay Point and Concord.
 Tri Delta Transit buses also connect with County Connection bus service, WestCAT bus service, Delta Breeze bus service and Amtrak at shared bus stops.
Bay Point, formerly West Pittsburg, 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 terminal 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.
San Ramon is a city in Contra Costa County, California, United States, located 15 miles east of San Francisco, and within the San Ramon Valley.
 San Ramon's population was estimated as 76,134 in mid-2015 by the US Census Bureau, making it the 4th largest city in Contra Costa County, behind Richmond, Concord and Antioch.

Question: California State Route 242 ends in which largest city of Contra Costa county?
Answer: Concord