There was a combined nearly $9 million of farms, ranches, hunting land and other land for sale in Seneca County, Ohio, recently on Land.com. The total size of all Seneca County farms, ranches, hunting land and other land for sale was approximately 1,000 acres. Seneca County ranks 72nd in the Buckeye State for the total acreage of land currently advertised for sale. Tiffin featured the most land for sale. Seneca County is Ohio's 22nd biggest county (552 square miles). It's located in the Northwest Ohio region of the state.