The well itself is a modest thing, a circular structure of drystone walling, roughly five feet in diameter according to a 1958 description, with an ash tree nearby and a worn path indicating long use. A modern drain now runs from it in a westerly direction. It appeared by its Irish name, Tobar Seanáin, on Ordnance Survey maps as far back as 1840 to 1841, and again on the 1914 revision, suggesting it had been a recognised feature of the landscape for generations before either survey was made.

The devotional practice centred on the well follows the pattern common to Irish holy wells, involving rounds, that is, a prescribed number of circuits made while reciting the Rosary, with pebbles picked from the stream used to count each completed round. Three drinks of water were taken, and the water was also used to bathe sore eyes and skin complaints. Rags, ribbons, medals, and small religious objects were left on the overhanging branches, a practice recorded consistently across accounts gathered from children at Leanamore, Tarmon East, and Tarbert schools in the mid-twentieth century. The three principal days of devotion were the Saturdays before May Day, St John's Day, and Michaelmas. Those accounts also preserve the origin legend: St Senan, the sixth-century founder associated with Scattery Island on the Shannon, was said to have struck a spring from the ground while travelling through the area, blessed it, and promised cures to those who came in faith. One account notes that a man named John Buckley later had the well properly sunk, lined, and planted around with trees, rescuing it from neglect. The well's most striking legend, that its water cannot be brought to the boil, appears in every variant of the tradition, each with a slightly different cast of characters. In one version the well vanishes overnight after the attempt and reappears across the road; in another it moves from a farm owned by a Mr Elliot to a neighbouring field; in a third a priest says Mass at the relocated well and its sanctity is formally restored. The fish that surfaces to cure the faithful appears in some accounts but is flatly denied in others, a rare instance of folk tradition openly disagreeing with itself.