[1][2] Once called Broad Water, it lies at the northern end of Kirkstone Pass, affording views on the descent towards Patterdale.

Dorothy Wordsworth, having left William Wordsworth sitting on Cow Bridge, walked beside the lake on 16 April 1802, commented on: ...the boughs of the bare old trees, the simplicity of the mountains, and the exquisite beauty of the path...the gentle flowing of the stream, the glittering, lively lake, green fields without a living creature to be seen on them.The lake is not among the most popular in the national park, being shallow and full of reeds.

Some of the buildings still contain spinning-rooms where villagers would have made their own clothing, selling any surplus in the local market towns.

The word Hartsop means "valley of the deer", which would have lived in the woodlands of the lower areas of the surrounding fells.

The lake is home to a trout population and harbours a rare species of fish, the schelly.