Florida is relatively flat and featureless, compared to the landforms of other major regions containing lakes in the United States. Nonetheless, subtle differences in topography help to define the occurrence of major lake types and their geochemistry. Most acidic or low ANC lakes in Florida are seepage lakes that lie in ridge and highland regions where a veneer of deep acid sands isolates the lake basin from the underlying limestone bedrock (cf. Figure 12.1, Chapter 12, Pollman and Canfield, this volume, and Figure 1, Southeast Overview, this volume). These Pleistocene sands are highly weathered, and groundwater seepage to these lakes provides little in the way of base cations and ANC. Acidic lakes in Florida are divided almost equally into two categories: (1) colored lakes, in which acidity is related to high concentrations of organic acids and (2) clearwater lakes, in which acidity is due to strong acids, principally H2SO4.