The Seminole Indian Nation occupied the area in its last major defiance of the resettlement plans of the young American republic; and the great Seminole warrior, Osceola, headquartered in the dense, eastern forests along the banks of the Withlacoochee River and the broad Lake Tsala Apopka. But alas, the Seminole cause was lost and the natives were moved west.

In 1842, Congress encouraged settlement in the peninsula of territorial Florida by establishing the Armed Occupation Act. The law granted a patent for 160 acres to any man who kept a gun and ammunition, built a house, cultivated five acres of this land and lived there for at least five years. Settlers moved in to take advantage of the generous land deal. The area contained abundant timber and suitable farm land, appealing attributes to the frontiersman. In 1845 Florida was granted statehood.

During the War between the States, a sugar mill was operated on the Homosassa River, supplying sugar to the Confederacy. A robust citrus growing industry developed in the eastern part of the area and it became a focus of intense economic expansion soon after the war.

In 1884 the farmers and growers were given a boost when the Florida Orange Canal and Transit Company built a canal from the groves to the Lake Panasoffkee railhead in what is now Sumter County. Barging through the canal and along the Withlacoochee River avoided the long and difficult overland wagon hauls to move the fruit to markets in the East. Citrus County was originally part of Hernando County; but through the efforts of Senator Austin S. Mann, the Florida legislature established Citrus County on June 2, 1887.

In 1894-95 the Big Freeze ended the vibrant citrus industry; but coincidentally, hard rock phosphate was discovered and a new, highly prosperous phosphate boom was underway. Steam shovels replaced the hand-pick and shovel and miners were sought from as far away as Georgia and South Carolina. The population soared to over ten thousand; 96 percent were of African-American descent. World War I terminated the flow of phosphate to European markets; the mines closed, and the population plummeted.

The area reverted to a benign, agricultural community until the great rush of retiree migration began. The current population is in excess of 100,000.

Citrus County's two incorporated cities are Inverness, the county seat, and Crystal River. Several significant unincorporated areas harbor the majority of the population, however. These areas are Beverly Hills, Homosassa, Homosassa Springs, Citrus Hills, Lecanto, Sugar Mill Woods, Floral City, Citrus Springs, Hernando, Holder, Citronelle and Ozello.