Coordinates: 53°15′34″N 4°25′01″W / 53.2593454°N 4.417015°W / 53.2593454; -4.417015
Trewalchmai is a village and a community in Anglesey, Wales. It is located just off the A5 road 5 miles west of Llangefni.
The Community's population in the 2011 census was 1009.