According to information compiled by former Albuquerque mayor David Rusk, 105 referenda were held in the United States between 1902 and 2010 to consider proposals to consolidate cities and counties. Only 27 of these proposals were approved by voters.
Wyandotte County, Kansas, uses the term "unified government" to refer to its consolidation with Kansas City, Kansas, and most of the towns within the county boundaries in which some cities and towns remain separate jurisdictions within the county. Individual sections of a metropolitan or regional municipality may retain some autonomous jurisdiction apart from the citywide government.
The case of New York City is unique, in that the city consists of five boroughs, each of which is co-extensive with a county. Each borough, being coterminous with a county, has its own district attorney; however, county-level government is essentially non-existent as all executive and legislative power is exercised by the city government throughout the five boroughs. The city, as currently constituted, was created in 1898 when the city of New York (then comprising what would become the boroughs of Manhattan and The Bronx) annexed Kings County, Queens County, and Richmond County as the boroughs of Brooklyn, Queens, and Staten Island, respectively.
In eight consolidated city-county governments in the United States, the formerly independent incorporated places maintain some governmental powers. In these cities, which the United States Census Bureau calls "consolidated cities", statistics are recorded both for the entire consolidated government and for the component municipalities. A part of the consolidated government is called the "balance", which the Census Bureau defines as "the consolidated city minus the semi-independent incorporated places located within the consolidated city".
Hartsville and Trousdale County, Tennessee (Despite the consolidated city-county government, Hartsville is not coterminous with Trousdale County; Hartsville remains a geographically distinct municipality within the county.)
Houma and Terrebonne Parish, Louisiana (Despite the consolidated city-county government, Houma is not coterminous with Terrebonne Parish; Houma remains a geographically distinct municipality within the parish.)
Washington, D.C. – While the District of Columbia is a federal district and not a county, the city has had a consolidated municipal government since 1871. Prior to then, Washington, Georgetown, and the unincorporated County of Washington were separate jurisdictions within the District of Columbia. Prior to 1846, when it was retroceded to Virginia, the south bank of the District of Columbia was the County of Alexandria (now the independent City of Alexandria and the County of Arlington).
Lafayette Parish, Louisiana and Lafayette (The status of the current state of consolidation is under review by an independent board. Deconsolidation, reorganization and total incorporation are all being considered as other towns in the parish as well as citizens in the unincorporated areas feel they are being under-represented under the current state of consolidation.)
Aurora, Colorado, split between three counties, explored the creation of a new consolidated city-county in 1996; the effort subsequently failed in a referendum. However, five years later nearby Broomfield was successful in creating a new city-county from portions of the four counties it had been a part of. Encouraged by Broomfield's experience, an Aurora city councilman has proposed consolidation again in 2006. This was not accomplished in 2006 or 2007, and no bills to accomplish consolidation were introduced in the 2008 session of the Colorado legislature.
A report was released in April 2008 recommending the merger of the governments of the City of Pittsburgh, Pennsylvania and that of Allegheny County. This plan has been endorsed by the mayor of Pittsburgh and the Chief Executive of Allegheny County, but needs approval by the City and County councils and from the state legislature before a referendum can be put forth for the voters to approve such a merger.
The independent City of St. Louis, Missouri and that of St. Louis County. The city of St. Louis seceded from St. Louis County in the 1870s and is not part of any county in the state of Missouri. The city has since tried to rejoin the county several times, each time rejected by county voters.
passed referendums in 1925, 1929 and 1939 that were blocked by technicalities by the state assembly. A partial consolidation of area school districts in 1956. Currently has a task-force researching consolidation since 2005.
held referendums in 1969 and 1990 to consolidate the two governments. Both times, city voters approved consolidation while county voters were opposed. The independent city of Salem, Virginia, which would have been surrounded by the consolidated entity, did not participate in the referendums. Vinton, Virginia would have retained its status as a town in the 1990 referendum. The consolidation issue has been dormant since 1990.
The City of Boston and Suffolk County, Massachusetts operated with a consolidated government for most of the twentieth century with Boston providing office space, auditors, budget, personnel and financial oversight for Suffolk County. This was not a true consolidation because three municipalities – Chelsea, Revere and Winthrop – were never annexed into Boston and remained separate jurisdictions within Suffolk County; however, the City of Boston held complete control of the county by law. The special relationship between Boston and Suffolk County ended in 1999 as part of the gradual abolition of county governments through much of the state with all county employees and powers transferred to Commonwealth of Massachusetts control. The only remaining powers and duties for the City of Boston in regards to the county is ceremonial in which the Suffolk County Register of Deeds is issued the oath of office at the start of a term as well as calls for a meeting to hold a special election to fill the office should there be a failure to elect someone to the office or a vacancy occurs.