The mill serving Aberllefenni Quarry was built in the early 1860’s and later extended. It housed 20 table saws and was powered by two large water wheels at either end of the building, fed through slate-lined leats from the nearby reservoir. The remains of these wheels remain in situ, underneath the concrete floor. The reservoir provides water for cooling and washing at the mill which remains in use.
Aberllefenni village consists of ‘Pensarn’, a terraced row of fourteen houses dating from 1860’s, a chapel originally built in 1839, enlarged in 1859 and rebuilt in 1874, the surviving part of the seventeenth-century Plas Aberllefenni, and the mid-nineteenth century quarry office and belfry for summoning workers.