In 1870-72, John Marius Wilson's Imperial Gazetteer of England and Wales described Gwnnws like this:
GWNNWS, or LLANWNNWS, a parish and a sub district in Tregaron district, Cardigan. The parish lies on the river Ystwith, 6½ miles N of Tregaron r. station, and 12 SE of Aberystwith; and consists of the two townships of Lower Gwnnws and Upper Gwnnws. Post town, Devil's Bridge, under Aberystwith. Acres, 17, 959. Real property of L. G., £1, 373: of U. G., £1, 527. Pop., of L. G., 535; of U. G., 760. Houses, 105 and 146. An increase of pop. in U. G., to the amount of 128, occurred in the ten years prior to 1861; and was caused by then extension of lead mining.. ...
The living is a vicarage in the diocese of St. Davids. Value, £106. Patron, Sir A. P. Chichester, Bart. A monumental stone, to the memory of a prince called Caradock, is in the churchyard. There are a Wesleyan chapel and a national school.The sub-district includes also three other parishes. Acres, 33, 140. Pop., 3, 423. Houses, 698.
A Vision of Britain through Time includes a large library of local statistics for administrative units. For the best overall sense of how the area containing Gwnnws has changed, please see our redistricted information for the modern district of Ceredigion. More detailed statistical data are available under Units and statistics, which includes both administrative units covering Gwnnws and units named after it.
GB Historical GIS / University of Portsmouth, History of Gwnnws, in Ceredigion and Cardiganshire | Map and description, A Vision of Britain through Time.
Date accessed: 26th July 2016
Click here for more detailed advice on finding places within A Vision of Britain through Time, and maybe some references to other places called "Gwnnws".