Coordinates: 51°36′48″N 3°23′55″W / 51.6132°N 3.3986°W / 51.6132; -3.3986
Llwyncelyn (English: Hollybush) is a district of Porth, Rhondda Cynon Taf.
Consisting of five long terraces and two modern housing developments, Llwyncelyn has one shop and a parish church, St. Luke's Church.
Llwyncelyn is also where Porth Harlequins RFC play their home rugby union matches.
Nearby Nyth-Brân Farm was the home of athlete Guto Nyth Brân.