Filled in around 1970, the well dedicated to Saint Mannan has effectively vanished from the landscape, yet it appeared on Ordnance Survey maps in 1839 and again in 1925, marked each time in gothic lettering as St. Mannan's Well. That gothic script was the cartographers' conventional signal for an antiquity, and the name itself conceals a further layer of obscurity: "Mannan" is a corruption of Moininne, an early Christian saint whose cult was once significant enough to draw people to this quiet Wexford valley every summer.

Moininne was, by any account, a figure of considerable standing in early Irish Christianity. She was reputedly baptised by Patrick himself, and the various traditions surrounding her connect her with both the Uí Eachach Cobha of County Down and the Cenél Eógain of Tyrone, suggesting her cult spread across several regions and dynasties. She founded a nunnery at Faughart in County Louth, a site already associated with the birthplace of Brigid, and she visited the island monastery of Beggerin in Wexford, which places her in this part of the country. Her most enduring foundation, however, was a convent at Killevy on the slopes of Slieve Gullion in County Armagh, a house that eventually became Augustinian and survived until the dissolution of the monasteries in the sixteenth century. Her feast day falls on the 6th of July, and it was on that date that a pattern, the Irish term for a devotional gathering at a holy well or sacred site, was held at this well in Woodtown. Writing around 1840, the scholar John O'Donovan noted that the pattern had continued until approximately 1810, after which it appears to have lapsed entirely.

The well itself has not been formally identified on the ground. Locally it is described as a natural spring, and it sits in a shallow valley running roughly northwest to southeast, with a stream about fifty metres to the northeast. The ruins of Kilmannan church lie roughly 320 metres to the north-northwest. What remains is essentially a place where something used to happen, a site stripped of its visible structure but still legible through its cartographic record and the saint's name that, even in its corrupted form, carried across two centuries of mapping.