A four-poster stone circle is a rectangular or sub-rectangular setting of four or five stones which are, or were once, upright. The corner stones of the rectangle are usually placed on the perimeter of a good circle, aligned on the cardinal points and are graded in height. The rectangle varies considerably in size from 13m squred to 345m squared. Four-poster stone circles may be recognised in the field as ruined standing structures or from antiquarian sketches. Other components which may be present are cupmarks on one or more of the stones, outlying standing stones, and a mound or cairn within the stone setting.
Four-poster stone circles should not be confused with megalithic settings whose slabs lie at ground level along the sides rather than at the corners of a rectangle or with wooden "four-posters" found in hillforts. They are to be distinguished from pairs of standing stones, standing stones and recent agricultural features which might bare a superficial resemblance to ruined four-poster stone circles.
Stone circles with more than four or five stones have been omitted from this description. They are described elsewhere as small stone circles.
However, when identifying four-poster stone circles there is some scope for confusion where stone triangles, for example seven included here on the North Yorkshire Moors, may or may not prove to be "Christianized" four-poster stone circles, whereby in the 19th century some stones were removed from monuments.
Only one four-poster stone circle in England has been excavated. Here it was suggested that the cairn within the stone setting contained a cremation space, already much disturbed. Investigation of Scottish four-poster stone circles has produced charcoal, bones and cremations in cists or pits, thereby maintaining a funerary role for this class of monument. They date generally to the Bronze Age.