| Official Name: | Fort Seneca, Ohio |
| Settlement Type: | CDP |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Ohio |
| Subdivision Type2: | County |
| Subdivision Name2: | Seneca County |
| Unit Pref: | Imperial |
| Area Footnotes: | [1] |
| Area Total Km2: | 1.62 |
| Area Land Km2: | 1.62 |
| Area Water Km2: | 0.00 |
| Area Total Sq Mi: | 0.63 |
| Area Land Sq Mi: | 0.63 |
| Area Water Sq Mi: | 0.00 |
| Population As Of: | 2020 |
| Population Total: | 230 |
| Population Density Km2: | 141.61 |
| Population Density Sq Mi: | 366.83 |
| Timezone: | Eastern (EST) |
| Utc Offset: | -5 |
| Timezone Dst: | EDT |
| Utc Offset Dst: | -4 |
| Elevation Ft: | 699 |
| Coordinates: | 41.2044°N -83.1678°W |
| Postal Code Type: | ZIP code |
| Postal Code: | 44883 |
| Area Code: | 419 |
| Blank Name: | GNIS feature ID |
| Blank Info: | 2628892 |
Fort Seneca is a census-designated place in Pleasant Township, Seneca County, Ohio, United States. It is located on State Route 53, approximately North of Tiffin. The population was 230 at the 2020 census.
Fort Seneca was built nearby in Jul. 1813 by Gen. William Henry Harrison during the War of 1812. The community of Fort Seneca was platted in 1836, and named after Old Fort Seneca, which was located 2 miles away from the present town site.[2]
Fort Seneca had a post office, with the ZIP code of 44829 until 1998.[3] The post office was opened on December 15, 1821.