The site is named "Bryn Factory" only on the 3rd edition of the 25-inch O. S. map of 1919; on the previous editions it is named as "Factory (Woollen)". The site is now occupied by a dwelling house rebuilt in 2006 using sawn slate blocks. An ornately engraved slate plaque records "PENYBONT FACTORY was built Anno Domini 1806 E Williams Jane Jones Jno Thomas". The factory was served by a leat shared with the adjacent Dorothea Slate Works (NPRN 411144), whose buildings it may have taken over by 1900.
W J Crompton, RCAHMW, 2 July 2010.