| Siam | |
| Settlement Type: | Unincorporated community |
| Pushpin Map: | USA Ohio |
| Pushpin Map Caption: | Location within the state of Ohio |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Ohio |
| Subdivision Type2: | County |
| Subdivision Type3: | Township |
| Subdivision Name3: | Reed |
| Unit Pref: | Imperial |
| Population As Of: | 2000 |
| Population Density Km2: | auto |
| Timezone: | Eastern (EST) |
| Utc Offset: | -5 |
| Timezone Dst: | EDT |
| Utc Offset Dst: | -4 |
| Elevation Ft: | 958 |
| Coordinates: | 41.0847°N -82.8783°W |
| Postal Code Type: | ZIP codes |
| Postal Code: | 44807 |
| Blank Name: | FIPS code |
| Blank1 Name: | GNIS feature ID |
| Blank1 Info: | 1049178 |
Siam is an unincorporated community in Reed Township, Seneca County, Ohio, United States. This town is also known as Attica Junction. CSX and NS intersect here. It is located along State Route 4, just north of Attica. The community is served by the Attica (44807) post office.[1]
Siam was originally called Detroit; under the latter name had its start in 1875 when the railroad was extended to that point.[2] A train station was soon built, which was called Attica Station. The post office in the community was operated under the name Siam. The Siam post office opened in 1878, and was discontinued in 1938.[3]