Toberacloon, in the townland of Cartron in County Mayo, follows the Irish naming convention for holy wells, "tobar" meaning well or spring, and the site does retain the essential character of one: a gathering of water in a particular place, quietly distinct from its surroundings. What you find here is not a tidy stone-lined well of the kind often associated with pilgrimage sites, but something wilder and less legible, an irregular pool roughly ten metres across, enclosed within a dense thicket of reeds, bog myrtle, and marsh vegetation.

The pool sits on the line of a stream or drain that also marks the boundary between townlands, a detail that hints at the way water features were once used to define territory as much as to serve devotional purposes. To the north and north-west the ground rises; to the south it opens into flat, wet land. A rough stone wall runs along the southern edge of the pool, following the same townland boundary line. The pool is at least a metre deep, with a soft, muddy base, and the vegetation pressing in around it gives the whole place a quality of enclosure that is quite different from the surrounding bog. Bog myrtle, a low shrub common in Irish wetlands, has a sharp, resinous scent, and in season it would make the approach to the pool noticeably aromatic before it becomes visible.