The township is bordered on the north by Grand Lake Saint Marys, forming a very irregular boundary, on the east by Auglaize County, on the south by Marion Township, and on the west by Butler Township. Franklin Township is six miles across from east to west and is about three and one-half miles from north to south. It contains about twenty-one sections.

Franklin Township contains 14,386 acres. At the settlement, two small bands of Indians occupied part of this territory. They were known as the "Big" and "Little" Chickasaws. These Indians were peaceful and never gave any trouble to the settlers. The five one-room school houses in Franklin Township were the Klosterman School on Guadulupe Road, Center School on State Route 219, Franklin School on County Road 219A, Liberty School at the corner of St. Johns Road and Clover Four Road, and Montezuma School in Montezuma. In 1941 the one-room schools were closed and a township school was built on the edge of Montezuma. This was called the Franklin School and is still in use today. This was a four-room school with two grades in each room. In 1955, it was decided to add four more rooms to the school. This allowed one grade per room. In 1960, by a vote of the people the Franklin School District was added to the Celina City Schools, and the high school students all were to go to Celina. Prior to this, high school students had their choice of either going to Celina or Coldwater. In 1964, the seventh and eighth grade classes were sent to Celina Junior High, giving Franklin School extra rooms to use for special classes. They now have a kindergarten and a media center.

Franklin Township has four public cemeteries. The township has one village, Montezuma. Its location on the south side of Grand Lake makes the tourist trade very important. There are numerous landings, marinas, trailer courts and camp grounds.

The area is agricultural with farms of all sizes. There are some who specialize in dairy, grain, poultry, hog, beef, and alfalfa.

The Lakefield Airport is located in Franklin township, as well as the Mercer County Waterfowl Refuge. The 1990 census showed Franklin Township had a population of 2.325.