The Zadock Thompson entomological collection is the oldest and most complete collection of its kind in the state of Vermont. It is also the largest insect collection in the state, with approximately 280,000 pinned specimens, and 20,000 DNA-grade specimens preserved in ethanol. The species represented in the collection represent the diversity of insect’s populations in Vermont, though the range of the specimens is worldwide. The collection consists of approximately 40% Coleoptera, 10% Hemiptera, 10% Diptera, 10% Lepidoptera, 5% Hymenoptera and 5% Odonata, and a selection of various other orders of insects; as well as 60,000 Arachnids. The collection is now the only large arthropod collection in the state, since the ruin of the State Invertebrate Collection by flooding from Tropical Storm Irene. The Thompson collection has repeatedly and regularly been accessed by scientists studying taxonomy, nomenclature, phylogenetics, population ecology, and biodiversity of species living in Vermont, as well as being regularly used for biological class instruction, and by non-biologists, including artists and photographers. Understanding the consequences of climate change on biodiversity and distribution of animals is becoming increasingly important, and thus the scientific value of historical collections such as the Zadock Thompson Zoological Collection increases.