On the grounds of Portraine Demesne in north County Dublin, a holy well dedicated to St Kenny once drew enough visitors, or at least enough local significance, to be marked by name on the Ordnance Survey's six-inch map of 1837. By the time the same surveyors returned to produce the more detailed twenty-five-inch edition in 1863, the designation had quietly shifted to 'St Kenny's Well (Site of)'. Within a single generation, a living place had become an archaeological parenthesis. Today, no surface remains are visible, and no local tradition survives to explain who came here, what they sought, or when the last visit was paid.

Holy wells across Ireland were typically associated with a patron saint and used for patterns, a word for the devotional gatherings, often held on a saint's feast day, that combined prayer with communal assembly. The saint here, Kenny, is likely St Cainnech of Aghaboe, a sixth-century Irish monk with dedications scattered across several counties. Immediately to the east of the well site lay a chapel, recorded in the archaeological inventory as DU012-009001, which suggests the well was once part of a small ecclesiastical complex rather than an isolated curiosity. The pairing of well and chapel was common enough in early Christian Ireland; the well provided ritual water and a focus for outdoor devotion, while the chapel served the more formal liturgical needs of the community. The scholars Ó Danachair, writing in 1958, and Healy in 1975, both noted the absence of surviving tradition, meaning that even within living memory of mid-twentieth-century research, no one locally could say much about what the site had once meant.

Portraine Demesne sits on the Fingal coast, a low-lying peninsula between the Rogerstown and Malahide estuaries. Because no surface trace of the well remains, there is little to see in any conventional sense, and the site sits within private demesne grounds. For anyone with a particular interest in the cartographic archaeology of vanished sacred sites, the 1837 OSi six-inch map, freely accessible through the Ordnance Survey Ireland historic map viewer, gives the clearest picture of where the well once stood relative to the surrounding landscape. The chapel site to the east is separately recorded and may reward further archival investigation for those tracing the early ecclesiastical geography of north Dublin.