The foundations of Melin Hermon were laid on 8 May 1743 on behalf of the Bodorgan Estate. The 1st and 2nd editions of the 25-inch O.S. maps, 1889 and 1900, show the mill as a working mill, but the 3rd edition, 1918, labels it as disused. The tapered rubblestone tower is 9.5 metres high and 6.4 metres internal diameter; the walls are 0.75 metres thick. The east doorway has a fine cambered head comprising six voussoirs with an extended keystone, and above it is an eroded and illegible plaque. In 1975 the major internal timbers supporting the first and second floors were in place, as was the second floor. In 2006 the tower above the second floor was open to the elements, but the two lower storeys had been converted to a store.
W J Crompton, RCAHMW, 3 September 2008.