Seasonal forest pools (SFPs), also known as woodland vernal pools or simply vernal pools, are common throughout the forests of the northeastern United States. SFPs are inundated during all or part of the period between late fall of one year and late spring to mid-summer of the subsequent year. The pools dry every year or at sufficient frequency to preclude the establishment of fish populations, are preferred breeding habitat for a number of amphibian species, and support a rich, diverse, and abundant macroinvertebrate community. These pools exist as aquatic “islands” in a “sea” of forest, and occur over a range of sizes, degrees of isolation, and hydroperiod lengths. As islands, pool area and isolation should affect the composition of biotic communities. The hydroperiod of ephemeral wetlands has been considered a third “island” attribute and is also known to affect biotic composition. We surveyed aquatic, benthic macroinvertebrates (BMIs) for two years using leaf-packs in 24 SFPs, representing a broad range of surface areas, inter-pool distances (isolation), and hydroperiods. Nearly 35,000 specimens of 76 taxa were enumerated from 198 leaf-pack samples. Chironomidae and Oligochaeta were the most abundant and most common taxa. BMI richness and diversity were positively, but weakly, related to maximum pool surface area, but not to pool isolation. The same results were found for permanent resident and predator taxa. BMI richness and diversity were positively related with pool hydroperiod, as reported from numerous other studies of ephemeral aquatic habitats.