54.6028°N, 3.0983°W.
Castlerigg Stone Circle stands on a low natural plateau above the town of Keswick in Cumbria, England, ringed on every side by the high fells of the northern Lake District. It is one of the earliest stone circles in Britain, conventionally dated to about 3200 BCE in the early Neolithic, and consists of 38 standing stones of local Borrowdale volcanic tuff arranged in a flattened ring roughly 32 by 30 metres in diameter, with an unusual ten-stone rectangular setting added inside the eastern arc whose function remains unexplained. The tallest stone reaches 2.3 metres; a clear gap on the north side flanked by two larger portal stones reads as an entrance. Castlerigg has the strongest visual relationship of any British circle with the surrounding landscape — High Seat, Skiddaw, Blencathra, and Helvellyn each frame a separate sector of the horizon — and the site was sketched by William Wordsworth, John Keats, and J. M. W. Turner in turn. The site was acquired by the National Trust in 1913 and has been continuously visited since.
Castlerigg was already ancient when the sarsens went up at Stonehenge.