Why Jacksonville Is the Largest City by Area

The City of Jacksonville makes that claim, but Census gazetteer figures show the Greeley County unified government in western Kansas with slightly more land, though far less total area once Jacksonville's water is counted.

The City of Jacksonville's economic development office calls Jacksonville the largest city in area in the continental United States (City of Jacksonville, About Jacksonville). The Census Bureau's 2024 Florida place gazetteer gives Jacksonville city 747.266 square miles of land and 127.193 square miles of water, about 874.5 square miles in all (2024 Gazetteer, Florida places).

The fine print sits in the Kansas file. The same 2024 gazetteer lists Greeley County unified government (balance) at 777.417 square miles of land and no water (2024 Gazetteer, Kansas places), about 30 square miles more land than Jacksonville and roughly 97 square miles less total area. The two official sources therefore support different versions of the claim: Jacksonville leads on total area, while Greeley County leads on land.

Nationally Jacksonville is not the largest at all. The 2024 Alaska county gazetteer lists four city and borough or municipality governments with far more land: Sitka City and Borough at 2,870.101 square miles, Juneau City and Borough at 2,702.924, Wrangell City and Borough at 2,556.097 and Anchorage Municipality at 1,707.069 (2024 Gazetteer, Alaska).

Jacksonville covers so much land because the City of Jacksonville and Duval County merged into one government on October 1, 1968, moving the city limit out to nearly the whole county.

Residents of Jacksonville and Duval County approved consolidation in August 1967 with 65 percent of the votes cast, and Consolidation Day followed on October 1, 1968 (Jacksonville Sheriff's Office history). The Census Bureau's historical tables show what that did to the map. In 1960 Jacksonville city had 201,030 residents on 30.2 square miles (Census 1998 working paper, Table 19); in 1970 it had 528,865 residents on 766.0 square miles (Table 20).

A few pieces of Duval County stayed outside. The county elections office lists Atlantic Beach, Baldwin, Jacksonville Beach and Neptune Beach as separate government offices (Duval County Supervisor of Elections), and their land is why Duval County's 762.623 square miles of land exceed Jacksonville city's 747.266 (2024 Gazetteer, Florida counties). The Census Bureau's 1998 working paper on large cities counts Jacksonville among five consolidated cities that include at least 90 percent and sometimes 100 percent of the populations of their parent counties (Census Working Paper 27).

Much of Jacksonville is not urban at all, and the Census Bureau has classified the city as partly rural since 1970.

The 1998 working paper explains that starting in 1970 the Bureau identified extended cities, where a portion of the land area and its population are defined as rural even though within official city boundaries, and its notes list Jacksonville as a consolidated city classified as partly rural from 1970 to 1990 (Census Working Paper 27). The urban part of Jacksonville covered 344.3 square miles in 1970, 394.6 in 1980 and 445.9 in 1990, well short of the full city.

A large share of the rest is parkland, marsh and water. The City of Jacksonville says it has the largest urban park system in the country, with more than 80,000 designated acres, including the 46,000-acre Timucuan Ecological and Historic Preserve (Jacksonville Parks, Recreation and Community Services). The National Park Service describes the Theodore Roosevelt Area of that Jacksonville preserve as a 600-acre natural treasure of hardwood forest, wetlands, and scrub vegetation (Timucuan Ecological and Historic Preserve, NPS).

Consolidation made Jacksonville one of the thinnest big cities in the country, and in 1990 it had the lowest density of the 20 largest U.S. cities.

The Census Bureau's Table A for 1990 ranks Jacksonville 15th by population with 635,000 residents on 759 square miles, a density of 800 people per square mile (Census Working Paper 27, Table A). Every other city in that top 20 had at least 2,000 people per square mile; New York had 23,700, and Houston, the next largest by land at 540 square miles, had 3,000.

The 1970 table puts the post-consolidation city at 690 people per square mile, against 6,657 in the old 30.2 square mile city of 1960 (Table 20; Table 19). By 1990 the figure had risen to 837 (Table 22). Dividing the 2020 Census count of 949,611 (Census 2020, Jacksonville city) by the 747.266 land square miles in the 2024 gazetteer gives about 1,271 people per square mile for Jacksonville in 2020.

Among consolidated city and county governments in the lower 48, Jacksonville stands out mainly because Duval County is large.

The Census working paper lists five consolidated cities in its tables: Jacksonville, Florida (1970-1990); Columbus, Georgia (1980-1990); Indianapolis, Indiana (1970-1990); Lexington, Kentucky (1980-1990); and Nashville, Tennessee (1970-1990) (Census Working Paper 27). In its 1990 table, Indianapolis covered 361.7 square miles against Jacksonville's 758.7 (Table 22), so the Jacksonville merger produced a city about twice the size of the Indianapolis one.

The same paper notes that Oklahoma City, which is not on its list of consolidated cities, was also classified as partly rural from 1970 to 1990. Jacksonville got its footprint differently, in one countywide vote in 1967 instead of a long run of annexations, which is why the Jacksonville city line has barely moved since 1968: 766.0 square miles in the 1970 table, 758.7 in 1990 and 747.266 in the 2024 gazetteer.

One mayor and one 19-member City Council govern nearly the whole of Duval County, with 14 members elected by district and five at large.

The City of Jacksonville describes a strong mayor form of government under which residents elect the mayor and the council, and it counts approximately 1,007,189 residents (City of Jacksonville, About Jacksonville).

Consolidation also merged agencies that had served the old city and the county separately. The Jacksonville Sheriff's Office history records that the Duval County Road Patrol and the Jacksonville Police Department united at consolidation under a new name, the Office of the Sheriff Jacksonville Police (Jacksonville Sheriff's Office history), and the same history counts T.K. Waters, elected in November 2022, as the seventh Sheriff of Duval County since 1968.

Last verified: October 18, 2026, by comparing the 2024 Census gazetteer files for Florida, Kansas and Alaska, rereading the Census Bureau's 1998 large-cities working paper and its 1960, 1970 and 1990 tables, and checking the City of Jacksonville, Jacksonville parks, National Park Service and Jacksonville Sheriff's Office pages.