There is a hole in the priest's door of Llandetty's church, and a story has grown up around it. Colonel Jenkin Jones, a local Parliamentarian and Puritan, is traditionally said to have fired at the door in 1660, furious at the return of Charles II, then turned his horse and ridden off. Whether the mark is really his is a matter of local faith rather than record. Visitors still come to look at it.
The church, St Tetti, sits above the south bank of the Usk in a sloping churchyard with three old yews and, in spring, daffodils and bluebells. It is isolated and opening hours can vary, so it is worth checking locally before you walk out to it. Inside are a 13th-century octagonal font, 17th-century floor ledgers and an 18th-century wall painting of the Hanoverian royal arms. Set into the fabric is the Llandetty Stone, an inscribed pillar dating to the 9th century. The present nave and chancel are largely 13th-century, and the building was restored in 1872.
Two areas of the churchyard hold the graves of 310 former servicemen who lived at the nearby British Legion home at Crossfield House, now Buckland House. They share a single collective monument rather than individual headstones. After a history-festival open day in 2022, the church secretary Keren Bender described "a real buzz of community in the church."
Llandetty is barely a village at all: a scatter of farms and houses in the Bannau Brycheiniog National Park, strung between the River Usk and the Monmouthshire and Brecon Canal. Since the hamlet has no pub or shop of its own, the towpath does the work, carrying you about two miles in either direction — a walk of roughly forty minutes — to Talybont-on-Usk and Llangynidr.
In Talybont-on-Usk, the Star Inn has a large garden beside the river and welcomes dogs; the White Hart, an old coaching inn, faces the village at the front and the canal behind, and keeps five changing beers. Talybont Stores combines a shop, post office and canalside café, where the kitchen runs from full breakfasts and wholetail scampi to Bombay pav bhaji, with an Indian evening menu.
Llangynidr has two more pubs. The Coach & Horses, run by Jak and Meghan, sits on the canal bank with a beer garden, games room, pool and darts; the kitchen sends out the Coach & Horses Burger, Welsh beef madras, a South African boerewors roll, Meg's lasagne and pies from Cashells of Crickhowell. It pours a Rhymney ale alongside two rotating guest beers. The Red Lion, on Duffryn Road, cooks seasonal food and Sunday roasts and stocks Welsh ales.
The canal between the two villages is the obvious walk, and Llandetty's church stands about 2.1 miles along it from Tal-y-bont. The full route from Tal-y-bont to Llangynidr runs 3.3 miles, past Ashford Tunnel, Parsons Bridge, old Great Western Railway boundary markers and Workhouse Bridge, and ends at the Llangynidr lock flight, where five locks fall seventeen metres over half a mile.
The canal was engineered by Thomas Dadford, who followed the contours of the Usk valley; the workhouse it once served still stands above the water near Work House Bridge. George Overton, who built the Brinore tramroad from Talybont to carry coal and quarry stone, moved to Llandetty after finishing it in 1815.
Crickhowell, six miles off, has a Thursday farmers' market, and Brecon and the medieval buildings at Tretower Court and Castle are both within reach. The nearest station, Abergavenny, is about fourteen miles away by road; the number 43 bus between Brecon and Abergavenny will stop at the church on request.
Llandetty Hall Farm's local history tells of Crafty, a horse buried in a nearby field in 1887 by Edmund Gwynne, once chief constable of Brecknockshire. The headstone reads "A noble animal."