What is a tarn?

The classic definition is a 'small mountain lake'. But the Vikings, who gave us the word when they described the Cumbrian landscape in which they settled 1100 years ago, knew nothing of classic definitions. They called any small water body a 'tjorn', from which the word tarn is derived. It means 'a small lake', or more poetically 'a teardrop'.

Where can I find tarns?

There are over two thousand tarns and pools in Cumbria. It is difficult to know the exact number because landscapes do not stand still.

Click here for a map of tarns in the Lake District (pdf)

Although found across Cumbria, tarns have become icons of the high fells, associated with remote, wilder places. The majority of tarns lie in the mountainous terrain of the Lake District National Park.

How were tarns created?

In the fells of Lakeland, the hard, resistant, volcanic rocks dominate, underpinning the scenery of rugged relief and climbing crags for which the area is famous. The structure of these rocks is also susceptible to the erosional processes needed for tarns to form.

Away from the central fells the geology changes. There are few tarns on the slaty, rocks north and west of Keswick, which weather differently giving smoother, gentler scenery.

Outside the Lake District rock types are different again. A band of limestone wraps around the Lake District to the south and east. Tarns sit uncomfortable here as limestone is permeable and does not hold water. Further eats in the North Pennines there are only a handful of tarns scattered amongst hollows in the bogs.

Many of our tarns were formed in the last ice age that came to an end about 10,000 years ago.

Glaciers, hundreds of metres thick pressed down onto the ground beneath, freezing onto every knoll and rocky outcrop. Then as the ice moves under gravity, it tears out pieces of rock, some as small as sand grains, others as large as houses. This debris then helped the glacier to scrape, plough and grind the bedrock, thus forming large hollows in the ground. Over time, water has collected in these scoured hollows and tarns are born.

Click here for information on Cumbria Tarns project