"Under Spanish rule, Florida was divided by the natural separation of the Suwanee River into West Florida and East Florida.
Upon the purchase of Florida, (1819) by the United States of America, West Florida and East Florida became two counties: Escambia County and St Johns County, so named and so ordained as counties with respective county governments by Andrew Jackson, Military Governor of the Territory of Florida."
Escambia and St. Johns counties, each named for Florida rivers, are created in the areas that were formerly East and West Florida, respectively, by military ordinance under Governor Andrew Jackson.
Duval County — named for then-Governor William Pope Duval — is created in the northern area of St. Johns County, above the mouth of the Suwannee River.
Jackson County — named after former Governor Andrew Jackson — is created in the area of Escambia County between the Chocwatachee and Suwannee rivers.
Gadsden County is created in the area of Jackson County between the Apalachicola River and the Suwannee River, taking its name from James Gadsden, Jackson's former aide.
The southern area of St. Johns County — south of the Caloosahatchee River and Lake Okeechobee — becomes Monroe County, named for then-President James Monroe.
The panhandle is further subdivided with the addition of Walton and Leon counties, the latter named for Ponce de León who led the first European expedition of Florida.
East of the Suwannee River St. Johns County is greatly downsized, having a majority of its former sprawl become Mosquito County. Alachua County is also formed at this time, comprising the western halves of Duval and St Johns counties.
Finally, the northern area of Duval County becomes Nassau County, named after the German Duchy of Nassau.
Washington County, named after former President George Washington, is formed from the western half of Jackson County.
Leon County is divided in to four counties. From West to East: Leon County — now a fraction of its former size, Jefferson County, Madison County, and Hamilton County. The new counties are named after former Presidents Thomas Jefferson and James Madison, as well as founding father and former Secretary of the Treasury Alexander Hamilton.
The southern section of Gadsden County becomes Franklin County, after Benjamin Franklin, while the northern reached of Alachua County become Columbia County, after an old poetic name for America.
Fayette County was also created in name, but never assigned any territory. Thus it is listed below, but cannot be found on the map.
Hillsborough County is created, occupying the southern half of Alachua County. It is named after Wills Hill, who had served as the British Secretary of State for the Colonies.
Monroe County is halved, its eastern half becoming Dade County. The new county is named in honor of a fallen soldier in the Second Seminole War, Major Francis L. Dade.
Calhoun County, named for former Vice President John Caldwell Calhoun, is formed from the southern area of Jackson County.
In the panhandle, Santa Rosa County — after Saint Rosa de Viterbo — and Wakulla County are created from the eastern portion of Escambia County and the southern area of Leon County, respectively. Alachua County's size is greatly reduced, having no less than three new counties taking part of its territory: Levy County, named for Representative David Levy; Hernando County, named after Spanish Explorer Hernando de Soto and later renamed to Benton County; and Marion County, in honor of General Francis Marion. In addition to much of Mosquito County's territory being reallocated to Hillsborough, Levy, and Marion counties, St. Lucia County is also created from former Mosquito County territory, spanning halfway across Florida from the East coast and through much of central Florida. The remaining area of Mosquito County was renamed Orange County due to the local citrus industry.
Holmes County is formed, occupying the northern area of Washington County and the western portion of Jackson County.
Putnam County — named for Benjamin A. Putnam a soldier in the First Seminole War and a legislator — is created East of Alachua County from parts of Alachua, Marion, St Johns, and Duval counties.
Benton County reverts to the name of Hernando County and later St. Lucia County becomes Brevard County, named for Judge Theodore W. Brevard. Sumter County is created from southern Marion County and named for General Thomas Sumter. To the East, Orange County is split and its coastal half becomes Volusia County. Liberty County is formed in the panhandle from south Gadsden County. The bottom half of Hillsborough County becomes Manatee County, named for the local population of manatees. In the north, Madison County is downsized, allowing for Taylor and Lafayette counties, named for President Taylor and the Marquis de Lafayette respectively, to be created. Clay County is established from a part of Duval County; it is named for Henry Clay, former Secretary of State. Finally Columbia County is divided in to three sections, allowing for the creation of Suwannee County to the west and New River County to the east.
New River County is divided, with the northern section becoming Baker County and the southern half being renamed to Bradford County. The counties are named for James McNair Baker, former Confederate Senator, and Captain Richard Bradford, the first Confederate officer from Florida to die in the Civil War, respectively.
In central Florida Sumter County is expanded, and the land to the south of it is split off from Hillsborough County to create Polk County, after President James K. Polk.
Hernando County is trisected, creating Citrus County to the north and Pasco County, named for Senator Samuel Pasco, to the south. Lake County is created from sections of Orange and Sumter counties in central Florida. Orange County is further downsized, along with Brevard County, as Osceola County is created in the center of the state, taking its name from the Seminole leader of the same name. Manatee County is moved to the west, now occupying the southern half of Hillsborough County, while most of its former area becomes De Soto County, named for Hernando de Soto. South of De Soto County, Lee County is established occupying most of the area of Monroe County General Robert E. Lee.
St. Lucie County is formed from the south half of Brevard (formerly St. Lucia) County. Later, to the south, Palm Beach County is created in the northern half of Dade County.
The region of Hillsborough County west of Tampa Bay becomes Pinellas County. In the panhandle, Bay County emerges around St. Andrews Bay from portions of Walton, Washington, and Calhoun counties. Meanwhile Seminole County is formed from areas of Orange and Volusia counties in central Florida and named after the indigenous tribe. Okaloosa County, its name meaning "black water" in Choctaw, is created between and from regions of Santa Rosa and Walton counties. Likewise, in the south, Broward County is created between Palm Beach and Dade counties, occupying land formerly of both counties; it is named for Governor Napoleon Bonaparte Broward. Parts of Osceola and St. Lucie counties along the northern shore of Lake Okeechobee become the newly-formed Okeechobee County, while on the east coast Flagler County, named for developer and railroad baron Henry Flagler, is created between St Johns and Volusia counties.
De Soto County is split into several parts, including the new counties of Hardee — named after Governor Cary A. Hardee, Highlands, Charlotte, and Glades. Union County is formed in the western area of Bradford County, while Sarasota County is created in the southern half of Manatee County. Dixie County is created out of part of Lafayette County, which along with Alachua County also gives up some of its land to form Gilchrist County – taking its name from Governor Albert W. Gilchrist. Lee County's size is reduced as two new counties, Hendry and Collier, are created in the east and south of the county, respectively. The names for these counties come from Major Francis A. Hendry, one of the first settlers, and Barron Collier, a prominent landowner. Northern Palm Beach County becomes Martin County, after Governor John W. Martin. One county to the north, Indian River County is created from a section of St Lucie County. Finally, in the panhandle, Gulf County is created from the southern half of Calhoun County.
"1868 Constitution (Article V, Section 7). The State shall be divided into seven judicial circuits with one circuit judge appointed to each circuit. Article XVI, Section 3 specifically listed the counties composing the seven judicial circuits as the following:
First Circuit: Escambia, Santa Rosa, Walton, Holmes, Washington, Jackson; Second: Gadsden, Liberty, Calhoun, Franklin, Leon, Wakulla, Jefferson; Third: Madison, Taylor, Lafayette, Suwannee, Columbia; Fourth: Nassau, Duval, Baker, Bradford, Clay, St. Johns; Fifth: Putnam, Alachua, Levy, Marion, Sumter; Sixth: Hernando, Hillsborough, Manatee, Polk, Monroe; Seventh: Volusia, Brevard, Orange, Dade."
"[...] The State shall be divided into seven judicial districts, the limits of which are defined in this Constitution, and one judge shall be assigned to each circuit. [...]"
"1903 Amendments to 1885 Constitution (Article V, Section 8). The 1903 Amendments to the 1885 Constitution increased the number of circuits from 7 to 8.
Eighth: Alachua, Bradford, Levy, Putnam, Baker."
"The State shall be divided by the Legislature at its first regular session after the adoption of this section, into eight Judicial Circuits, and one Judge shall be assigned to each Circuit. Such Judge shall hold at least two terms of his Court in each county within his circuit every year, and at such times and places as shall be prescribed by law, and may hold special terms."
"In 1911, the Legislature created the Ninth, Tenth, and Eleventh Circuits and restructured the first eight circuits.
First: Escambia, Santa Rosa, Walton; Second: Gadsden, Leon, Wakulla, Franklin, Jefferson, Liberty; Third: Madison, Taylor, Lafayette, Suwannee, Hamilton, Columbia; Fourth: Duval, Nassau, Clay, St. Johns; Fifth: Marion, Citrus, Hernando, Sumter, Lake; Sixth: Hillsborough, Pasco; Seventh: Orange, Osceola, Volusia, Brevard, St. Lucie; Eighth: Alachua, Bradford, Levy, Putnam, Baker; Ninth: Washington, Holmes, Jackson, Calhoun; Tenth: Polk, Manatee, DeSoto, Lee; Eleventh: Palm Beach, Dade, Monroe."
You can view the original Chapter Law creating the Ninth, Tenth, and Eleventh Circuits here.
"1934 Amendments to the 1885 Constitution (Article V, Section 8). 1934 Amendment to the 1885 Constitution provided that there be fifteen judicial circuits and that no circuit have a population of less than 50,000 persons. As a result of the population threshold imposed by the Legislature on the circuits, many of the circuits had to be restructured to comply with the constitutional population requirements. In 1934, the judicial circuits in Florida were as follows: First: Escambia, Santa Rosa, Okaloosa, Walton; Second: Franklin, Gadsden, Leon, Wakulla, Jefferson, Liberty; Third: Madison, Taylor, Lafayette, Suwannee, Hamilton, Columbia, Dixie; Fourth: Duval, Clay, Nassau; Fifth: Marion, Citrus, Hernando, Lake, Sumter; Sixth: Pinellas, Pasco; Seventh: Volusia, Putnam, St. Johns, Flagler; Eighth: Alachua, Baker, Gilchrist, Bradford, Union, Levy; Ninth: Brevard, Orange, Osceola, Seminole, Indian River, Okeechobee, St. Lucie, Martin; Tenth: Polk, Hardee, Highlands; Eleventh: Dade, Monroe; Twelfth: Manatee, Sarasota, DeSoto, Charlotte, Glades, Lee, Hendry, Collier; Thirteenth: Hillsborough; Fourteenth: Holmes, Washington, Bay, Jackson, Calhoun, Gulf; Fifteenth: Broward, Palm Beach."
"In 1951, The Legislature divided the Eleventh Circuit, so that it encompassed only Dade County, and created a Sixteenth Circuit for Monroe County."
"In 1963, the Legislature divided the Fifteenth Circuit, so that it encompassed only Palm Beach County, and created the Seventeenth Circuit for Broward County. (Chapter 63-470, Laws of Florida)."
"In 1967, the legislature divided the Ninth Circuit into three circuits, leaving Orange and Osceola as the Ninth Circuit, incorporating Brevard and Seminole Counties as the Eighteenth Circuit, and incorporating Indian River, Martin, Okeechobee, and St. Lucie Counties as the Nineteenth Circuit."
"In 1969, the Legislature created the Twentieth Circuit: Charlotte, Collier, Glades, Hendry, Lee."
"The legislature may establish not more than twenty judicial circuits, each composed of a county or contiguous counties and of not less than fifty thousand inhabitants, according to the last census authorized by law, except that the county of Monroe shall constitute one of the circuits; provided, however, there shall be no reduction in the number of circuit judges residing in any county formerly a part of a judicial circuit, which circuit is hereafter created, divided, changed or revised."