Florida's present sixty-seven counties evolved from the original two counties (St. Johns, all of the territory east of the Suwannee River, and Escambia, from the Suwannee west to the Perdido River) established by Andrew Jackson in 1821. As Florida's population increased, existing counties were partitioned to create new ones, and by 1840 twenty counties had already been established. County boundary maps of the nineteenth century show the proliferation of counties in northern Florida where economic activity and population were concentrated. With twentieth century technological advances, all of Florida, and especially the previously sparsely populated southern peninsula, became available for more intense development.
By 1925, when Gilchrist County was established, all sixty-seven of Florida's present-day counties had been formed. Boundary adjustments, necessitated by political, economic, and physical land changes, however, have continued. Thirty formal boundary adjustments have been made by the Florida legislature since 1925. For example, construction of a major highway effectively isolated a small rural part of Duval County. The isolated part was legislatively transferred to Clay County through a series of formal boundary changes in 1976, 1978, and 1980. Another more recent boundary adjustment occurred in 1986 when the line between Franklin and Wakulla counties was changed from the eastern shore of the Ochlockonee River to the "thread" (center) of the river. This change officially moved several small islands from Franklin County into Wakulla County.
Not all of the counties established in the nineteenth century are still in existence. Mosquito County, created in 1824, originally included all of Seminole Indian territory within its boundaries. In 1845, through a name change, it became Orange County. Fayette County was created in 1832 and went out of existence in 1834. In 1844 Hernando County, established in 1843 from part of Alachua, was renamed Benton to recognize a U.S. senator who sponsored the Armed Occupation Act of 1842, which made free land available for settlers to homestead in southern Florida. The name was changed back to Hernando in 1850 when Benton fell out of favor with extremists in the Florida legislature. New River County, established in 1858 from part of Columbia, was split to become Baker County and a much smaller New River County early in 1861. Late in 1861 what remained of New River was renamed Bradford County in honor of Captain Richard Bradford, a Florida military officer who was killed in battle barely two months before the name change. St. Lucie County was created as St. Lucia in March of 1844 from part of Mosquito County. In 1855 it was renamed Brevard and its county seat of Ft. Pierce was renamed Susannah. In 1917 St. Lucie County was reestablished and today its county seat is again Ft. Pierce. Efforts were made to establish two other counties (Call, 1828, and Bloxham, 1917) as evidenced in legislative documents, but neither was officially created.
