Felin Forgan is at the bottom of the gorge of the Afon Llifon which comes down from the direction of Maes Tryfan, several hundred yards closer to the plain than the mill of Ffatri Tryfan. Felin Forgan was a corn and grain mill. A trough or mill stream carried water from the gorge to the wheel. 

According to the property deeds, the Morgan in question was most probably the Reverend Morgan. The earliest written mention of there being a mill on the site is Dr Thomas Parry's reference to one Robert Morris who was a miller in 1802, when he competed with an ode in an eisteddfod in Llanddeiniolen. This would make the mill over 222 years.

Much of the land surrounding the mill was in the ownership of Lord Newborough, and at one stage the  mill and farmland referred to as Felin Forgan appear to have been on separate titles. It is unclear as to whether Lord Newborough also owned the mill, so there is still much research to be done.

It is noted that William Williams was the miller when the tithe map was drawn up in 1840. According to the 1841 census, the property was then called Rhaeadr (Rhaiadr) Llifon, with William Williams, his wife and eight children living there. 

In 1851, Richard Thomas is recorded as having lived there, with Hugh Thomas was named as the miller. In 1861, Daniel Eames farmed the land at Felin Forgan. He was a successful trader who employed a porter, namely Thomas Jones.  Owen Jones worked as the miller for Daniel Eames but by 1891, the mill was in the care of his widow Frances and his two sons, Owen and Richard. By 1899, Frances seems to have remarried to Thomas Jones, a worker at Felin Forgan. Frances died in 1906 and her son Owen lived there until he moved to Benisarhos, Y Groeslon in 1914. 

From 1915, David E. Jones and his family lived in the mill until his death in 1923. Evan Roberts and Sarah his wife came there at some point after this, and left in 1944, when an Englishman called Bazzard bought the property and surrounding farmland. It is thought that the mill worked for a short time,  though he mainly marketed and sold hay, straw and milk around the area. 

In 1968, the mill and farm was purchased by the Buddle family, who ran the property as a small-holding, caravan site  and market-garden until the early 80's. The mill has remained within that same family's ownership for over 50 years. 

Feiln Forgan is still standing and is in remarkable condition for its age. The remains of the water wheel are also present, but this is in serious need of attention as by now the metal frame  is very corroded and all the wooded sections have rotted away. The original workings and grindstones are also largely intact, though the upper floor surrounding the stones is now very dangerous. The course of the mill stream through the nearby meadow, and upper dam with sluice gate are all still visible but have been dry for decades. It is said that an attempt to re-fill the dam was made during the late 50's, which resulted in a huge flood to the lower lying fields and farm yard. This has not been attempted since! In more recent years, the exterior of the mill and its surroundings have been utilised as a film-set and also as the subject matter of several paintings and sketches by visiting artists who were inspired by this imposing building and its idyllic, unspoilt surroundings.