In a similar manner to the now vanished Broadstones not far from here, Coate circle is directly on a modern day road. The last traces of the circle can just about be seen as an arc of stones in a field. The road obviously passed through the centre of the ring at one time.

Coate Stone Circle (this link goes nowhere)

This picture was taken from the side of the road. The road runs away to the right outside the shot. If you move your mouse over the photograph, I have highlighted the positions of the less obvious stones. They prescribe an arc - half the original circle.