Llanycrwys sits on the banks of the River Twrch, Carmarthenshire County, South Wales. The hamlet sits south east of Llangybi, south west of Cwrt-y-cadno and close to Ffarmers.
The village is just over 2km from the border between Ceredigion and Carmarthenshire.
The hamlet lies in a rural location with pasture and arable land.
The Roman Road 'Sarn Helen' passes close to Llanycrwys. Sarn Helen runs from Aberconwy in the north of Wales to Carmarthen in the south.
The parish church is dedicated to St David.
Nearby mountains include Craig Siarls(390m), Carn Nant-yr-ast(440m) to the north east and Pen Taseithin(415m) to the south west.