There was a combined nearly $7 million of farms, ranches, hunting land and other land for sale in Seneca County recently on Land.com. The total size of all Seneca County land and rural real estate for sale was 1,000 acres. Seneca County ranks 75th out of 88 counties in the Buckeye State for the total acreage of land currently advertised for sale. Among cities in Seneca County with land for sale, Tiffin had the most land for sale. Seneca County is Ohio's 22nd largest county (552 square miles). It's located in the Northwest Ohio region of the state.