Unified government

In United States local government, a consolidated city-county is a city and county that have been merged into one unified jurisdiction. As such it is simultaneously a city, which is a municipal corporation, and a county, which is an administrative division of a state. It has the powers and responsibilities of both types of entities.

A consolidated city-county is different from an independent city, although the latter may result from consolidation of a city and a county and may also have the same powers as a consolidated city-county. An independent city is a city not deemed by its state to be located within the boundary of any county and recognized by its state as a legal territorial entity separate from surrounding or adjoining counties. A consolidated city-county differs from an independent city in that the city and county both nominally exist, although they have a consolidated government, whereas in an independent city, the county does not even nominally exist.

Not considering Hawaii, which has no independent cities, the Midwest and Upper South have the highest concentration of large consolidated city-county governments in the United States, including Indianapolis, Indiana; Nashville, Tennessee; Jacksonville, Florida; Louisville, Kentucky; Kansas City, Kansas; and Lexington, Kentucky. Currently, the largest consolidated city-county in the United States by population is Philadelphia, Pennsylvania, while the largest by land-area is Sitka, Alaska.

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.

...
Wikipedia