Summit Township, formed in 1841, is located in the western part of Crawford County and is bounded on the north by Summerhill, on the east by Hayfield and Vernon, on the south by Sadsbury and on the west by Pine and Conneaut.  It is six miles in length and four in width.

Harmonsburg, the only village of the township was laid out in 1816 by Henry Broadt and serves as the center of the Township.  The northern portion of Conneaut Lake lies within the township and includes Conneaut Lake Amusement Park.