Franklin Township, one of eleven in Warren County, Ohio, is in the northwest corner of the county. It is the most populous township in the county, the 2000 census finding 27,294 people there, down from 27,510 in 1990. It is named for Benjamin Franklin.

Franklin Township is bounded on the south by Turtlecreek Township, on the west by the Butler County townships of Lemon and Madison, on the north by the Montgomery County townships of German and Miami; and on the east by Clearcreek Township.

One of the original four townships of Warren County, it was created on May 10, 1803 when the county was just nine days old. At that time, it was much larger. On August 5, 1804, the southern part was transferred to the newly created Turtlecreek Township. On September 11, 1815, the eastern part was transferred to the newly created Clearcreek Township. The original western boundary was the Great Miami River, but Clinton County proved a continuing headache to the legislature and forced adjustments to Warren County. The Ohio Constituion requires that every county have an area of at least four hundred square miles and Clinton County's boundaries were several times adjusted in an effort to comply with that clause of the constitution. One of them, the Act of January 30, 1815, detached a strip of land from the eastern side of Warrren County to give to Clinton. That would have left Warren under four hundred square miles, so a portion of Butler County (the part of Franklin Township where Carlisle is now located) was attached to Warren in compensation. The 1815 act was as follows:

• Section 1--That all that part of the county of Butler lying and being withing the first and second fractional townships in the fifth range, and adjoining the south line of Montgomery County, shall be and the same is hereby attached to and made part of the county of Warren.
• Section 2--That eleven square miles of the territory of the county of Warren and extending parallel to the said eastern boundary of Warren County, along the whole lenth of such eastern boundary from north to south, shall be and the same is hereby attached to and made a part of the county of Clinton."

A large part of the township is in the cities of Franklin and Carlisle, but parts are in the cities of Middletown and Springboro. In November 2004, the people of Franklin Township and the City of Franklin will vote on a committee to study merging the two communities.

Other communities in the township are Hunter, Blue Ball, and Chatauqua.

Most of the township is in the Franklin City and Carlisle City School Districts, but parts are in the Springboro City and Middletown City School Districts. Telephone service is provided through the Franklin, Middletown, Miamisburg, Centerville, and Germantown exchanges, while mail is provided through the Franklin, Carlisle, and Middletown post offices.

Interstate 75 runs through the township, as do State Routes 122 and 73. The Miami and Erie Canal formerly ran through the township.