Plas Yolyn is a good-looking, ashlar-faced house of the closing years of the eighteenth century, of whom the architect’s name is sadly currently unknown. The house has a mid eighteenth-century core – and may incorporate earlier elements – and yet owes its current external appearance to a through remodelling for William Challoner. The main front has a central three-bay section with a single-storey pedimented Doric portico and a half-storey divided from the lower two storeys by a dentillated cornice. To each side are lower two-storey bays with tripartite windows.

Plas Yolyn had belonged to the Edwards family of nearby Kilhendre (q.v.) since at least the sixteenth century when Timothy Edwards, who married Alice, daughter of Adam Colfox in 1575, was described as of both Kilhendre and Plas Yolyn.

John Morrall, of a family formerly from Whitchurch, married Judith Edwards of Kilhendre in 1669 and seems to have received Plas Yolyn, perhaps as her dowry. His eventual successor, Josiah Morrall (1702–1745), a surgeon of Holywell, left Plas Yolyn to his wife and she, in turn, sold the property to her brother-in-law William Challoner of Iscoyd.

Challoner’s son and namesake was High Sheriff of Shropshire in 1800 who died in his year of office. His sister, Frances Challoner (b. 1746), married her cousin, Charles Morrall (1748–1822), and, on her brother’s death in 1800, the property passed to Charles and Frances. Charles Morrall, a surgeon at Chester, had inherited Kilhendre and sold that estate to concentrate his resources on Plas Yolyn.

In 1837, Plas Yolyn was owned by Charles Morrall (1775–1839), but occupied by W. Hilton. In 1851 the property was recorded as being the residence of the solicitor Robert Morrall but it was then owned – along with neighbouring Plas Warren (q.v.) – by Edward Morrall (1777–1858). He was described as ‘of Liverpool’ yet was successful in augmenting the family’s possessions by acquiring the Lordship of Traian from the Earl of Powis in 1823.

By 1906, Cyrus Morrall (1854–1912) – the son of Rev. Cyrus Morrall (1804–1882), the former vicar of St Michael’s, Liverpool, and North Leigh, Oxfordshire – was living there. He was also the owner of nearby Plas Warren.

In the middle years of the twentieth century, Plas Yolyn passed through the female line from the Morralls to the Curteis family and remains in that family’s ownership.