| Country: | Wales |
| Official Name: | Bylchau |
| Coordinates: | 53.154°N -3.532°W |
| Static Image Name: | St Thomas's Church, Bylchau - geograph.org.uk - 1161058.jpg |
| Static Image Caption: | St Thomas's Church, Bylchau |
| Community Wales: | Llansannan |
| Unitary Wales: | Conwy |
| Constituency Welsh Assembly: | Clwyd West |
| Constituency Westminster: | Bangor Aberconwy |
| Post Town: | DENBIGH |
| Postcode District: | LL16 |
| Postcode Area: | LL |
| Dial Code: | 01745 |
| Os Grid Reference: | SH976629 |
Bylchau is a hamlet in Conwy County Borough, Wales. It is located at the junction of the A544 with the A543, some 5 miles to the south-west of Denbigh, and just a mile from the county border with Denbighshire.
The village has a church, which was consecrated on 27 October 1857, and dedicated to St Thomas.[1]
Together with the village of Llansannan, the residents of Bylchau elect community councillors to represent them on Llansannan Community Council.[2]