Phytoplankton samples from nearshore stations along the Indiana coast of Lake Michigan were analyzed to determine the composition and seasonal abundance of phytoplankton populations. Occurrence patterns of major populations and population groups were inspected. As might be expected in a local inshore region where physical mixing and advection processes are relatively intense, phytoplankton distribution is highly variable. The largest general effect noted is a continuing increase in groups other than diatoms, apparently as a result of silica depletion. The singular exception to this trend is the abundant occurrence of Cyclotella comensis, a diatom which has only recently become abundant in Lake Michigan and can apparently tolerate very low silica levels. Specific to the region is an atypically high abundance of members of the diatom genus Nitzschia during some sampling periods.