| Derwenlas | |
|---|---|
 | |
  Derwenlas Location within Powys | |
| OS grid reference | SN723991 |
| Principal area | |
| Preserved county | |
| Country | Wales |
| Sovereign state | United Kingdom |
| Post town | MACHYNLLETH |
| Police | Dyfed-Powys |
| Fire | Mid and West Wales |
| Ambulance | Welsh |
| UK Parliament | |
Derwenlas is a hamlet in northern Powys, Wales. It is part of the community of Cadfarch.
Part of the historic county of Montgomeryshire (Sir Drefaldwyn) from 1536 to 1974, it lies on the River Dyfi and was once a port serving the market town of Machynlleth. Derwenlas lies on the A487 trunk road from Machynlleth to Aberystwyth.