The Parliamentarian New Model Army seized the mansion, but it was later taken by the opposite side, the Royalists under John Owen, who used it as his headquarters.

The family of Plas Hen (today named Talhenbont) descended from Collwyn ap Tangno [cy] (c.1000 – 1050), Lord of Ardudwy and Eifionydd, founder of the 5th of the Fifteen Tribes of Wales, c. 1137.

[1][2][3] The mansion standing today was constructed in 1607 by William Vaughan (d. 1633) of the House of Corsygedol, a dynasty started in Merionethshire by the Irishman Osbwrn Wyddel around the 13th century.

After successive family member-owners up until 1758, Plas Hen (Talhenbont), owned by the Vaughan family, became the largest privately owned single piece of land in the Welsh area of Eifionydd, it was also the largest estate of multiple halls and surrounding countryside in different locations in North Wales.

In 1845, Talhenbont Hall and surrounding land was purchased by the Ellis-Nanney family from the Mostyn baronets for £50,000 (equivalent to £7 million in 2023).

Talhenbont's exterior is a two-storey home with an attic made of rubble stonework with ashlar cut stone walls as a slate-roofed house with slate tiled copings.

There is a large central gable in the wing and a visible difference where the terminal stack shows where the original Hall and the new additions were merged.

Another ogee features over the original doorway on the southwest of the house of a Tudor arch with their family coat of arms above the door.

[3][12] The sculpted stone square tablet is inscribed; the initials WV, suggesting William Vaughan of Corsygedol, and the date of Talhenbont's construction in 1607.

Then the quarterly of Collwyn ap Tangno (5/15 Tribes of Wales), Osborn Wyddel, four lions passant (Kingdom of Gwynedd), and Ednyfed Fychan with the initials AV, presumably Ann Vaughan of Plas Hen.

[6][15] The coat of arms on the north front bears the family motto:[3] Latin: Non Nobis NatiWe are not born for ourselvesIn addition to the Hall, the 100-acre estate has outbuildings that have been converted into accommodation for use as part of a hospitality venue.

[6][19][20][21] In 2011, Talhenbont Hall was the subject of an episode of the BBC One Hidden Houses series, presented by Laurence Llewelyn-Bowen.