In medieval Gwynedd, Rhosyr was the royal demesne (Welsh: maerdref) and seat of governance for the commote of Menai.

The inhabitants were evicted during 1294 from east Anglesey to the west of the island by Edward I, in order to promote the new port of Beaumaris.

[1][4] In 1814, Newborough's status as a Royal chartered borough of King George III was abolished after the resignation of the town mayor.

There are six single-storey cottage homes attached to the institute; they were gifted to the village by Sir John Prichard-Jones, after whom the building was named; he was born in Newborough.

Sir John served as an apprentice draper in Caernarfon, then moved to London to work at Dickins, Smith and Stevens.

[1][8] Pritchard-Jones was eventually appointed as chairman of the Dickins & Jones department store in London, to which he gave his name.

[13] Just outside the village is Tacla Taid ("Grandpa's stuff"), the Anglesey Transport and Agriculture Museum, the largest of its kind in Wales.

[14] The village is in the Bro Aberffraw electoral ward on Anglesey, the area represents the south-west of the island.

[20] Today, the village gives its name to the Peerage of Ireland as Baron Newborough of the Welsh Wynn family.