Washington Township is one of the eighteen townships of Columbiana County, Ohio, United States.

The 2020 census reported 2,002 people living in the township.

Located in the southern part of the county, it borders the following townships: One village is located in Washington Township: It is one of forty-three Washington Townships statewide.

[5] 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,[6] 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.