[2][notes 1][3] Llandyssil takes its name from St Tysul, a little known Welsh saint of the 7th century.

For ecclesiastical administration, the parish was in the Bishopric of St Asaph, the Archdeaconry of Montgomery and the Deanery of Cedewain.

During the later part of the 18th century, it appears that the Welsh language was supplanted by English for general usage in the village.

[12][13] To the northeast is Ffridd Faldwyn, possibly the largest hillfort in Wales, which is adjacent to Town Hill in Montgomery.

The prehistoric sites include:[14] The medieval church of St Tysul formerly stood on the hillside overlooking the village.

It was extensively rebuilt in the 18th century with round arched windows and roof dormers.

[36] Now only a stone porch with an 18th-century doorway remains, standing in the churchyard.The current St Tysul's church, by the architect Thomas Henry Wyatt, was built between 1863–66.

The quoits court was moved to behind the Upper House pub by 1983, where Wales beat Scotland in an international match.

[46][47] The 2012 Welsh National Sheep Dog Trials were held on the field by the bridge at Henfron, Llandyssil, between 19 and 21 July 2012.