Duval County, Florida in the context of Consolidated city–county

Florida is a state located in the Southern United States. There are 267 cities, 123 towns, and 21 villages in the U.S. state of Florida, a total of 411 municipalities. They are distributed across 67 counties, in addition to 66 county governments. Jacksonville has the only consolidated city–county government in the state, so there is no Duval County government. However, smaller municipal governments exist within the consolidated municipality, e.g., Baldwin and the Jacksonville Beaches. All but two of Florida's county seats are municipalities (the exceptions are Crawfordville, county seat of rural Wakulla County; and East Naples, county seat of Collier County).

Municipalities in Florida may be called cities, towns, or villages, but there is no legal distinction between the different terms. As of the 2010 U.S. Census, more than 10 million Floridians, 55% of the state's total population of 18,801,310, lived in municipalities. The remainder lived in unincorporated areas. However, 92% of the population lives in urban areas, thus the actual number of residents living in truly rural areas is small. There are ten counties in the state with just one municipality and ten counties with only two.

The Julington-Durbin Preserve is a 2,031-acre nature preserve operated by the St. Johns River Water Management District in Duval County, Florida. The preserve shares the name of the two creeks that border the preserve and connect to the St. Johns River. Julington Creek is on the north side of the preserve, and Durbin Creek is to the south. The preserve has three designated hiking trails. Recreational activities include picnicking, horseback riding, bicycling, and hiking.

This is a list of the 100 most populous of the 3,144 counties in the United States based on the national decennial US census conducted on April 1, 2020, and vintage Census population estimates for July 1, 2024.

Many of the counties on the list include major cities or metropolitan areas in all parts of the United States. Seven of the listed counties have consolidated city and county government, namely the City and County of Honolulu, Metropolitan Government of Nashville and Davidson County, Tennessee, City and County of Philadelphia, City and County of San Francisco, City of Jacksonville and Duval County, Indianapolis and Marion County, and City and County of Denver. Kings County, Queens County, New York County, Bronx County, and Richmond County are coterminous with the respective boroughs of New York City; they fall under the jurisdiction of the combined Government of New York City. Independent cities are not counted.

Jacksonville (US: /ˈdʒæksənˌvɪl/ JAK-sən-vil) is the most populous city proper in the U.S. state of Florida, located on the Atlantic coast of northeastern Florida. It is the county seat of Duval County, with which the city consolidated in 1968. It is the tenth-most populous U.S. city and the largest city in the Southeast, with a population of 949,611 at the official 2020 U.S. census. The Jacksonville metropolitan area, at over 1.76 million residents, is the fourth-largest metropolitan area in Florida and 38th-largest in the United States. City-county consolidation greatly increased Jacksonville's official population and extended its boundaries, placing most of Duval County's population within the new municipal limits; Jacksonville grew to 900 square miles (2,300 km). It is the largest city by total area, land and water, in the contiguous United States.

Jacksonville straddles the St. Johns River in the First Coast region of northeastern Florida, about 12 miles (19 kilometers) south of the Georgia state line (25 mi or 40 km to the urban core/downtown) and 350 miles (560 km) north of Miami. The Jacksonville Beaches communities lie along the adjacent Atlantic coast. The area was originally inhabited by the Timucua. During Spanish rule, several missions were established in the Jacksonville area; the most prominent locally was San Juan del Puerto on present-day Fort George Island, which served the Mocama Timucua. In 1564, the French founded the short-lived Fort Caroline near the mouth of the St. Johns River. During the brief period of British rule (1763–1783), a settlement developed at a narrow point on the river where cattle crossed, known as Wacca Pilatka to the Seminole and "Cow Ford" to the British. In 1822, a year after Spain ceded Florida to the United States under the Adams–Onís Treaty, in exchange for U.S. recognition of Spanish sovereignty in Texas, a platted town was established there and named for Andrew Jackson, the first military governor of the Florida Territory and the seventh president of the United States.

Local governments in Florida are established by the state government, and are given varying amounts of non-exclusive authority over their jurisdictions. The laws governing the creation of local governments are contained in the Florida Constitution and the Florida Statutes. Local governments are incorporated by special acts of the Florida Legislature. These include four types: counties, municipalities, school districts, and special districts.

In some cases, municipal and county governments have merged into a consolidated government. However, smaller municipal governments can be created inside of a consolidated municipality/county. In Jacksonville, the municipal government has taken over the responsibilities normally given to Duval County, and smaller municipalities exist within it.

Baldwin is a town in Duval County, Florida, United States. When the majority of communities in Duval County were consolidated with the city of Jacksonville in 1968, Baldwin, along with Jacksonville Beach, Atlantic Beach and Neptune Beach, remained partly independent. Like the other towns, it maintains its own municipal government, but its residents vote in the Jacksonville mayoral election and vote for the Jacksonville City Council. Unlike the others, Baldwin no longer supports its own police force. The population was 1,396 at the 2020 census, down from 1,425 at the 2010 census. It is part of the Jacksonville, Florida Metropolitan Statistical Area.

The Jacksonville Beaches, or Jax Beaches known locally as "The Beaches", are a group of towns and communities on the northern half of San Pablo Island on the US state of Florida's First Coast. These communities are separated from the main body of the city of Jacksonville by the Intracoastal Waterway. The Jacksonville Beaches are located in Duval and northern St. Johns counties, and make up part of the Jacksonville metropolitan area. The main communities generally identified as part of the Beaches are Mayport, Atlantic Beach, Neptune Beach, Jacksonville Beach, and Ponte Vedra Beach.

Julington Creek is a waterway in Duval County, Florida widening out into the St. Johns River in the southern part of Jacksonville. Durbin Creek is a tributary. Julington Creek feeds into the St Johns River widening out into Old Bull Bay by the border of Duval and St. Johns County, Florida. It is navigable by paddlecraft and there are boat launches and a marina.

Formerly known as Julianton Creek, land surrounding it in the area of the Julianton Plantation was granted by British Governor of East Florida Patrick Tonyn to John Christian Ross. Ross was Scottish and part of a prominent family. He had two daughters with one of his slaves. He freed her and moved from Florida to Dominica in 1784, but died within the year. Their two daughters were sent to Edinburgh to live with his father John Ross of Arnage, Aberdeenshire, the "deaf and dumb laird". Arnage Castle was home to family members.

The Jacksonville Consolidation was the city-county consolidation of the governments of the City of Jacksonville and Duval County, Florida. It was effected on October 1, 1968.