Big Spring Township is one of the fifteen townships of Seneca County, Ohio, United States.Located in the southwestern corner of the county, it borders the following townships: The village of New Riegel is located in eastern Big Spring Township, and the unincorporated community of Alvada lies in the western part of the township.Big Spring Township also contains the unincorporated communities of Adrian and Springville.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.