Ravine ecosystems in Florida are known to support diverse biota, including Appalachian elements and endemic species, but little information concerning stream insects was known. This study documented caddisfly species diversity by repeatedly sampling adults and immatures at upper and lower reaches of ravine streams located within several different major drainage basins and biogeographic regions in northern Florida. The survey revealed a rich and distinctive fauna associated with ravine ecosystems, including many ravine crenobionts, narrow-range endemics, and species with disjunct distributions. At least 12 caddisfly species previously unknown to science were discovered, eleven of which were subsequently described and named. Steephead ravine streams in the western panhandle contain a highly endemic fauna, and the ravine fauna associated with the Apalachicola River has the strongest Appalachian affinities. Cluster analysis of the macrocaddisfly survey results placed study sites into groupings congruent with regional biogeography and stream type. Five distinct macrocaddisfly communities were identified. Community structuring appears to be controlled hierarchically by regional biogeography on a large scale and within-region habitat factors related to ravine type and flow characteristics on a smaller scale.