Conneaut Township is in western Crawford County, bordered to the west by Ashtabula County, Ohio. According to the United States Census Bureau, the township has a total area of , of which is land and , or 1.88%, is water. The northern end of the Pymatuning Reservoir, one of the largest reservoirs in Pennsylvania, is in the southwest. The township includes the unincorporated communities of Steamburg, Pennline, Conneaut Center, and Center Road, as well as the northern half of the Pymatuning North census-designated place.
