Florida’s unique geography results from its formation as a low-relief, limestone-based peninsula jutting into the Atlantic Ocean and Gulf of Mexico. The state’s landforms are distinct in the United States, defined by extremely low elevations and the pervasive influence of water and underlying geology. The three major landforms that shape the state are the vast Coastal Plain, the unique Everglades wetland system, and the underlying Karst topography.
The Dominant Landform: The Coastal Plain
The majority of Florida is geographically part of the Atlantic and Gulf Coastal Plain, a broad, flat expanse that extends far beyond the state’s borders. This landform is characterized by its extremely low average elevation, which is often less than 100 feet above sea level. The state’s highest point, Britton Hill, is only 345 feet, marking the lowest high point of any U.S. state. The plain is composed primarily of unconsolidated sediments like sand, silt, and marine deposits left behind as sea levels fluctuated over geological time.
This vast, flat landform slopes gently toward the coastlines, allowing for the formation of the state’s famous quartz sand beaches and extensive barrier islands. The subdued relief means that water drains slowly, contributing to the high water table that influences much of the state’s environment.
The Watery Interior: Wetlands and The Everglades
Florida’s interior is defined by extensive wetlands, with the Everglades standing out as a massive landform. The Everglades is not a swamp but a vast, slow-moving sheet of water, famously nicknamed the “River of Grass.” This shallow, wide river flows southward from the Lake Okeechobee area across a limestone shelf toward Florida Bay.
The low elevation and high water table across the state create bogs, marshes, and cypress swamps. In the Everglades, the slow flow, known as sheetflow, is about 100 miles long and up to 60 miles wide, covering an area where the vertical drop is only a few inches per mile. This hydrological system supports a diverse ecosystem adapted to the saturated environment.
The Hidden Geology: Karst and Sinkholes
Beneath the surface sediments of the Coastal Plain lies the Florida Platform, a massive, porous limestone layer formed from ancient marine organisms. This soluble bedrock is responsible for Florida’s widespread Karst topography, a landscape shaped by the dissolution of rock. Rainwater, which becomes slightly acidic as it filters through organic material, slowly dissolves the limestone over time, creating a network of underground conduits and caves.
Though often hidden, the effects of Karst are visible as distinct landforms such as numerous freshwater springs and sinkholes. Springs occur where underground rivers in the limestone reach the surface, providing a window into the Floridan Aquifer, a major water source. Sinkholes are depressions that form when the ceiling of an underground cavity collapses, representing a direct result of the chemical erosion of the underlying limestone layer.