List of United States counties and county equivalents in the context of "Micropolitan Statistical Area"

The municipalities of Puerto Rico (Spanish: municipios de Puerto Rico) are second-level administrative divisions defined with geographic boundaries and governmental authority in the archipelago and island of Puerto Rico, an unincorporated territory of the U.S. Amounting to 78 incorporated towns and cities equivalent to U.S. counties, two of which are outside the main island, namely the smaller islands of Vieques and Culebra, the municipalities are governed by a popularly elected strong mayor and unicameral legislature. They are subdivided into 902 barrios, third-level divisions controlled by the municipal government. As a jurisdiction under U.S. sovereignty, Puerto Rico does not have first-level administrative units akin to states or provinces.

The municipalities of Puerto Rico operate under the Municipal Code of Puerto Rico (Law. No. 107 of 2020), which superseded the Autonomous Municipalities Act of Puerto Rico (Law No. 81 of 1991), as established by the Legislative Assembly of Puerto Rico, the governmental body responsible for their organization under Section 1, Article VI of the Constitution of Puerto Rico. Electorally, the municipalities are grouped into eight senatorial districts and forty representative districts, representing roughly equal populations in the Legislative Assembly.

The Miami metropolitan area, officially known as the Miami–Fort Lauderdale–West Palm Beach Metropolitan Statistical Area, is a coastal metropolitan area in southeastern Florida. It is the sixth-largest metropolitan statistical area (MSA) in the United States, the third-largest metropolitan area in the Southern United States, and the largest metropolitan area in Florida. It is also known as South Florida, SoFlo, SoFla, the Gold Coast, Southeast Florida, the Tri-County Area, or Greater Miami. With a population of 6.45 million, its population exceeds 31 of the nation's 50 states as of 2023. It comprises the three most populated counties in the state, Miami-Dade County, Broward County, and Palm Beach County. Miami-Dade County, with 2,701,767 people in 2020, is the seventh-most populous county in the United States.

Miami is the region's financial and cultural core and most populous city. According to the Global and World Cities Research Network (GaWC) classification Miami is an "Alpha minus" city and is considered a very important world city that links the major economic region of South Florida into the world economy. The Global Financial Centres Index (GFCI 37) ranked Miami as the world's 26th most important finance center as of May 2025, ranking 7th in the United States only behind New York, San Francisco, Chicago, Los Angeles, Washington D.C. and Boston. Other principal cities, as defined by the Office of Management and Budget, include Fort Lauderdale, West Palm Beach, Pompano Beach, Boca Raton, Sunrise, Deerfield Beach, Miami Beach, Kendall, Doral, Delray Beach, Jupiter, and Palm Beach Gardens. The Miami metropolitan area is part of the larger South Florida region of the state, which also includes the Everglades and the Florida Keys.

Los Angeles County, sometimes abbreviated as LA County, is the most populous county in the United States, with 9,757,129 residents estimated in 2024. Its population is greater than that of 40 individual U.S. states. Comprising 88 incorporated cities and 101 unincorporated areas within a total area of 4,083 square miles (10,570 km), it accommodates more than a quarter of Californians and is one of the most ethnically diverse U.S. counties. The county's seat, Los Angeles, is the second most populous city in the United States, with 3,878,704 residents estimated in 2024. The county is globally known as the home of the U.S. motion picture industry since its inception in the early 20th century.

United States micropolitan statistical areas (μSA, where the initial Greek letter mu represents "micro-"), as defined by the Office of Management and Budget (OMB), are labor market and statistical areas in the United States centered on an urban cluster (urban area) with a population of at least 10,000 but fewer than 50,000 people. The micropolitan area designation was created in 2003. Like the better-known metropolitan statistical areas, a micropolitan area is a geographic entity used for statistical purposes based on counties and county equivalents. On July 21, 2023, the Office of Management and Budget released revised delineations of the various core-based statistical areas (CBSAs) in the United States, which recognized 542 micropolitan areas in the United States, four of which are in Puerto Rico.

The term "micropolitan" gained currency in the 1990s to describe growing population centers in the United States that are removed from larger cities, in some cases by 100 miles (160 km) or more.

Collin County is a county in the northern part of the U.S. state of Texas. It is part of the Dallas-Fort Worth-Arlington metropolitan statistical area, and a small portion of the city of Dallas is in the county. At the 2020 United States census, the county's population was 1,064,465, making it Texas's sixth-most populous county and the 43rd-largest county by population in the United States. Its county seat is McKinney.

This is a list of U.S. counties and county equivalents by gross domestic product in US$.