Querrin is unique on the Loop Head Peninsula. This sheltered shoreline and tidal inlet lies just west of Poulnasherry Bay between Corlis Point and Querrin Point. The characteristic feature of the place and forming the inlet is a sandbank extending from Corlis Point eastward to Querrin Point. It runs in a slight u-shape, first extending into the estuary and then circling back to the mainland which it meets at Querrin Pier (the tidal part of the sandbank stretches on to Querrin Point), leaving only a narrow channel for tidal waters to enter and exit the inlet. Underlying this sandbank is, at least in places, peat, similar to Rinevella Bay further west. Close to the rocky outcrop at Corlis Point sits a short stretch of vegetated shingle which disappears after about 100 meter under a sand dune and grassland habitat. This habitat extends for about 1.8 kilometres on top of the permanently exposed part of the sandbank all the way to Querrin Pier.
This dune and grassland area is the only of its kind on the peninsula and features an extremely diverse flora. Lady’s Bedstraw and the Pyramidal Orchid are the two more unusual wildflowers for the area which grow side by side with White and Red Clovers, Eyebright, Selfheal, Scentless Mayweed and many other species. Rabbits have made themselves a home here and the resident shelducks use their old burrows to nest.
The sheltered inlet to the north of the dunes features a mudflat but is dominated by a vast saltmarsh which extends from the eastern end of the dune grassland to Templemeeagh Graveyard at the western end of the inlet and from there along the shore of the mainland up to Querrin Pier. Only the main channel of the intertidal mudflat that connects the narrow opening of the inlet to an unnamed stream that enters the inlet at its western end, remains free of saltmarsh vegetation. This vegetation consists mainly of Common Cord Grass and Common Reed but Glasswort, Sea Aster and Sea Lavender are plentiful especially between the dunes and the saltmarsh proper.
The estuary side of the dunes features a sandflat, which is widely covered in shingle and pebbles, and a stretch of rocky shore near Corlis Point.
Querrin is one of the most important feeding and resting spots for waders and waterfowl at the Shannon Estuary. The resident birds – Oystercatcher, Snipe, Ringed Plover, Shelduck and others – are joined from September onward by the winter visitors: Redshank, Greenshank, Sanderling, Dunlin, Lapwing, Curlew, Teal, Wigeon and Brent Goose are among the more common species.