On the first, second and third editions of the 25inch OS maps published in 1889, 1900 and 1918, there is a farm called Nant-Pig situated on the coast of Porth Ceiriad, approximately two miles south west of Abersoch, on the southern tip of the Llyn Peninsula. On modern maps the site is a caravan park and campsite called Nant-y-Big
Sources: modern and historic OS maps, and http://www.nantybig.co.uk/ - the caravan park website.
M. Ryder, RCAHMW, 31st October 2018.