In a nine year study of the benthic environment of southeastern Lake Michigan, 90 taxa of Chironomidae were collected. Of these, 20 were present in sufficient quantities to provide information on densities, yearly population fluctuations, relationships to water depths, correlations with sediment types, growth (based on instars present), and emergence periods. Chironomus fluviatilis-gr. and Saetheria tylus were the numberically dominant species followed by Chironomus anthracinus-gr., Procladius spp., Cladotanytarsus sp., Cryptochironomus sp. 2, Polypedilum scalaenum, and Robackia demeijerei. Average density was greatest between 4-8 m deep (819 m-2) and decreased steadily to a minimum at >32 m (119 m-2). Several taxa occurred in all substrate types, but there was a general continuum of species associations from coarser to finer substrates with most associations in fine sands to silty/clayey sands. Taxa with primary distributions in water <12 m deep had peak emergence in summer, those with distributions between 12-20 m also showed some summer emergence, those >20 m primarily emerged in spring and fall.