Ffynnon Trillo is a spring located some 420m north of St Trillo's Church (NPRN 43904) . It is depicted on historic (1890-1901) Ordnance Survey mapping.

Sources include:
Ordnance Survey, 1890-1891, Landmark 25inch
Ordnance Survey, 1900, Landmark 25inch

RCAHMW, June 2012