In the United States, a county or county equivalent is an administrative or political subdivision of a U.S. state or other territories of the United States which consists of a geographic area with specific boundaries and usually some level of governmental authority. The term "county" is used in 48 states, while Louisiana and Alaska have functionally equivalent subdivisions called parishes and boroughs, respectively. Counties and other local governments exist as a matter of U.S. state law, so the specific governmental powers of counties may vary widely between the states, with many providing some level of services to civil townships, municipalities, and unincorporated areas. Certain municipalities are in multiple counties; New York City is uniquely partitioned into five counties, referred to at the city government level as boroughs. Some municipalities have been consolidated with their county government to form consolidated city-counties, or have been legally separated from counties altogether to form independent cities. Conversely, counties in Connecticut and Rhode Island, eight of Massachusetts's 14 counties, and Alaska's Unorganized Borough have no government power, existing only as geographic distinctions.
The municipalities of Puerto Rico are the second-level administrative divisions in the Commonwealth of Puerto Rico. There are 78 such administrative divisions covering all 78 incorporated towns and cities. Each municipality is led by a mayor and divided into barrios, third-level administrative divisions, though the latter are not vested with any political authority. Every municipality is governed as stated by the Autonomous Municipalities Act of 1991, which establishes that every municipality must have an elected strong mayor with a municipal legislature as the form of government. Each legislature must be unicameral, with the number of members related to adequate representation of the total population of the municipality. In contrast to other jurisdictions, both the mayors and the municipal legislators are elected on the same date and for the same term of four years in office.
An unincorporated area is a parcel of land that is not governed by a local general-purpose municipal corporation. There are many unincorporated communities and areas in the United States and Canada, but many countries do not use the concept of an unincorporated area.
A census-designated place (CDP) is a concentration of population defined by the United States Census Bureau for statistical purposes only.
The town is the basic unit of local government and local division of state authority in the six New England states. Most other U.S. states lack a direct counterpart to the New England town. New England towns overlie the entire area of a state, similar to civil townships in other states where they exist, but they are fully functioning municipal corporations, possessing powers similar to cities and counties in other states. New Jersey's system of equally powerful townships, boroughs, towns, and cities is the system which is most similar to that of New England. New England towns are often governed by a town meeting, an assembly of eligible town residents. The great majority of municipal corporations in New England are based on the town model; there, statutory forms based on the concept of a compact populated place are uncommon, though elsewhere in the U.S. they are prevalent. County government in New England states is typically weak, and in some states nonexistent. Connecticut, for example, has no county governments, nor does Rhode Island. Both of those states retain counties only as geographic subdivisions with no governmental authority, while Massachusetts has abolished eight of fourteen county governments so far. Counties serve mostly as dividing lines for the states' judicial systems and some other state services in the southern New England states while providing varying services in the more sparsely populated three northern New England states.
The United States Census Bureau defines a place as a concentration of population which has a name, is locally recognized, and is not part of any other place. A place typically has a residential nucleus and a closely spaced street pattern, and it frequently includes commercial property and other urban land uses. A place may be an incorporated place or it may be a census-designated place (CDP). Incorporated places are defined by the laws of the states in which they are contained. The Census Bureau delineates CDPs. A small settlement in the open countryside or the densely settled fringe of a large city may not be a place as defined by the Census Bureau. As of the 1990 census, 26% of the people in the United States lived outside of places.