A concentric stone circle is a prehistoric ceremonial or ritual monument comprising an arrangement of two or more stone rings set within one another. The recorded diameter of the outer ring varies from 19.8m to 331.6m and has between 20 and 97 stones, ranging in height from 0.9m to 2.2m, which are, or were once, set upright. The size of the inner circle(s) is of course dependent upon that of the outer circle. They are recognised in the field as concentric rings of standing or fallen stones. Other components which may be present are stone alignments, outlying standing stones, embankments, centre stones, inner cairns or mounds, burials, pavements, portal entrances or lintelled stones.Although many of the sites are similar in form the classification includes two exceptionally large and complex concentric stone circles, at Avebury and Stonehenge in Wiltshire, which because of several periods of reuse and modification are difficult to phase and interpret.
Concentric stone circles may be confused with other categories of stone circle, particularly large regular and irregular stone circles when they are badly ruined. They need also to be distinguished from decayed cairns with stone revetments and some types of ring cairn which may have a similar appearance.
Specifically excluded are those small stone circles which are uncertain classifications, but which may have two rows of very low stones, which probably once lay beneath cairns.
The monument class was probably current from the Late Neolithic to the end of the Early Bronze Age. They probably had a similar function to other stone circles.