Lón is a glacial river valley whose 30km-wide estuary is framed by Eystrahorn and Vestrahorn, two prominent spikes of granite to the east and west. The central Jökulsá i Lóni is a typical glacial flow, its broad gravel bed crisscrossed by intertwined streams that are crystal clear and shallow in winter but flow murky and fast with increased snowmelt in summer. A sandbar across the mouth of the bay has silted the estuary up into lagoons – lón in Icelandic – with good trout fishing, thousands of whooper swans nesting on the eastern side below Eystrahorn, and reindeer herds descending from the upper fells in winter.