In 1860, the eve of the Civil War, the southern edge of settlement, which delimited the “settled” areas with more than two persons per square mile from the “frontier” areas with fewer than two inhabitants per square mile, stood in central Florida. With the exception of a settled area along eastern Tampa Bay, the southern half of the Florida peninsula was a true frontier. South Florida, in fact, was the largest remaining frontier east of the Mississippi River.
Otto, John Solomon
"Florida's Cattle-Ranching Frontier: Manatee and Brevard Counties (1860),"
Florida Historical Quarterly: Vol. 64
, Article 5.
Available at: https://stars.library.ucf.edu/fhq/vol64/iss1/5