Fairfield Township is one of the fourteen townships of Madison County, Ohio, United States.

The 2020 census found 1,452 people in the township.

Located in the eastern part of the county, it borders the following townships: The communities of Kiousville and Lilly Chapel are located within the township.

[4] The township is governed by a three-member board of trustees, who are elected in November of odd-numbered years to a four-year term beginning on the following January 1.

There is also an elected township fiscal officer,[5] who serves a four-year term beginning on April 1 of the year after the election, which is held in November of the year before the presidential election.