| Country: | Wales |
| Official Name: | Trecastell |
| Coordinates: | 53.2067°N -4.4952°W |
| Cardiff Distance Mi: | 131 |
| London Distance Mi: | 218 |
| Unitary Wales: | Anglesey |
| Community Wales: | Aberffraw |
| Lieutenancy Wales: | Gwynedd |
| Constituency Welsh Assembly: | Ynys Môn |
| Constituency Westminster: | Ynys Môn |
| Post Town: | TŶ CROES |
| Postcode District: | LL63 |
| Os Grid Reference: | SH 3345 7064 |
Trecastell is a farm and historical site in the community of Aberffraw, Anglesey, Wales.
Llywelyn the Great, Prince of the Kingdom of Gwynedd, granted lands around Trecastell to Ednyfed Fychan. During the 14th century, Trecastell was the home of Tudur ap Goronwy, one of Ednyfed's descendants. He was a knight in the service of King Edward III of England, and a royal officer for Anglesey. He was also the namesake of the Royal house of his descendants; the House of Tudor.[1]