List of United States counties and county equivalents

There are 3,244 counties and county equivalents in the United States. The 50 states of the United States are divided into 3,007 political subdivisions of states called counties. Two hundred thirty-seven other local governments and geographic places are also first-order administrative divisions of their respective state/district/territory, but are not called counties. The United States Census Bureau refers to the latter as county equivalents. The 237 county equivalents include the District of Columbia and 100 equivalents in U.S. territories (such as those in Puerto Rico). The large majority of counties and equivalents were organized by 1970. Since that time, most creations, boundary changes and dissolutions have occurred in Alaska and Virginia.

Among the 50 states, 44 are partitioned entirely into counties, with no county equivalents. Louisiana is instead divided into 64 equivalent parishes, while Alaska is divided into 19 equivalent boroughs and 11 sparsely populated census areas, the latter also known collectively as the unorganized borough. Virginia is composed of a mixture of 95 counties and 38 independent cities. Maryland, Missouri and Nevada are each composed entirely of counties, except that each also has exactly one independent city: Baltimore, St. Louis, and Carson City, respectively. The District of Columbia is a single federal district that is not part of any state or county. All of the above 136 exceptional cases are reckoned as county equivalents. The number of counties (or equivalents) per state ranges from the three counties of Delaware, to the 254 counties of Texas. In New England, where the town model predominates, several counties have no corresponding local governments, existing only as historical, legal, and census boundaries, such as the counties of Rhode Island, as well as eight of Massachusetts' 14 counties. On June 6, 2022, the U.S. Census Bureau formally recognized Connecticut's nine councils of government as county equivalents instead of the state's eight counties. Connecticut's eight historical counties continue to exist in name only, and are no longer considered for statistical purposes. In total, the 50 states consist of 3,143 counties and equivalents.

Similarly, the Census Bureau treats 100 subdivisions of the territories of the United States as county equivalents. These are the 78 municipalities of Puerto Rico, the three major islands of the U.S. Virgin Islands, the three districts and two atolls of American Samoa, Guam as a single island and county equivalent, the four municipalities of the Northern Mariana Islands, and the nine island territories of the U.S. Minor Outlying Islands. As in the states, each territorial county equivalent has its own INCITS/FIPS codes.

Table
The following table lists the 3,143 counties and county equivalents of the United States with the following information for each entity:
 * 1) The entity name
 * 2) The state or equivalent (federal district or territory)
 * 3) The population as of April 1, 2020 as enumerated by the United States Census Bureau.
 * 4) The core-based statistical area if designated by the Office of Management and Budget
 * 5) The county's date of foundation