Somewhere in the low-lying callows south of the Slate River near Rathangan, a church has essentially vanished into the landscape, leaving behind only a tree-covered earthen mound and the faint outline of a ditch. The Ordnance Survey mapmakers, who documented Ireland's terrain with considerable thoroughness across multiple editions of their six-inch maps, never recorded this site at all. Yet it was there, and earlier cartographers knew it well enough to name it.

Two eighteenth-century maps of County Kildare preserve the memory of the place. Noble and Keenan's 1752 map marks it as 'Tamplenasonagh', while Taylor's 1783 map gives the name as 'Temple Summogh', both variants likely derived from the Irish word teampall, meaning a church or ecclesiastical site. By the time the Ordnance Survey was working the county in the nineteenth century, the site had apparently fallen below the threshold of recognition. What remains today is an oval earthen mound, roughly 41.5 metres east to west and 28.5 metres north to south, rising only one to two metres above the surrounding ground. Around its base runs a low retaining wall of mortared limestone flags and blocks, best preserved on the eastern, south-western, and western sides, and beyond that a shallow outer ditch. The upper surface, level and measuring about 19 metres by 7 metres, is covered in trees, and there is no visible trace of any church structure. The mound sits about 60 metres south of the Slate River, with a curving mill race running along its northern edge, a small detail that suggests the area was once worked as well as worshipped in.