  Trethomas Location within Caerphilly | |
| OS grid reference | ST185885 |
|---|---|
| Principal area | |
| Preserved county | |
| Country | Wales |
| Sovereign state | United Kingdom |
| Post town | CAERPHILLY |
| Postcode district | CF83 |
| Dialling code | 029 |
| Police | Gwent |
| Fire | South Wales |
| Ambulance | Welsh |
| UK Parliament | |
Trethomas[1] (English: Thomastown) is a small village 2+1⁄2 miles (4 km) northeast of Caerphilly, southeast Wales, situated in the Caerphilly county borough, within the historic boundaries of Monmouthshire.
It neighbours Bedwas and Machen, and forms a council ward in conjunction with those communities.