As of the 2020 census, 796 people lived in the township.

Located in the northern part of the county, it borders the following townships: A small part of the city of Wellston lies in far southeastern Washington Township, and the unincorporated community of Byer is located in the township's northwest.

[4] 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.