The Government of San Joaquin County is defined and authorized under the California Constitution and California law as a general law county. Much of the Government of California is in practice the responsibility of county governments, such as the Government of San Joaquin County. The County government provides countywide services such as elections and voter registration, law enforcement, jails, vital records, property records, tax collection, public health, and social services. In addition the County serves as the local government for all unincorporated areas. Some chartered cities such as Stockton and Tracy provide their own municipal services such as police, public safety, libraries, parks and recreation, and zoning. Some other cities arrange to have the County provide some or all of these services on a contract basis.