Probably the most widespread and numerous class of archaeological monument in Europe, and found in other parts of the world too. At the most basic a round barrow is simply a roughly hemispherical mound of soil, stone, and redeposited bedrock heaped over a central burial. Depending on the nature of the bedrock, such mounds may be predominantly stone (cairns) or earth. The basic pattern is elaborated by the range of constructional features and devices. Some examples have a surrounding ditch, which acted both to delimit the monument and as a quarry for material with which to make the mound. Kerbs are found round some mounds, while others have a gap or berm between the mound and the surrounding ditch. Compositionally some mounds are carefully made, with alternating layers of turf, soil, and stone forming successive envelopes, and in a few cases there are concentric rings of posts set in the original ground surface and giving structure to the mound. Stones are used instead of posts in some western areas of the British Isles. The central burial may be an inhumation, usually in a pit or cist, or a cremation, either in a pit or contained within an urn or a jar. As well as a central primary burial, many round barrows contain satellite burials added during the construction of the barrow mound. Secondary burials are often added to the mound, in some cases many centuries later.
The simplest round barrows are generally referred to as bowl barrows because of their shape, variations and more complicated forms being termed fancy barrows. In the British Isles the majority of round barrows are of Bronze Age date, but the tradition as a whole begins in the early Neolithic around 4000 bc and continues intermittently until late in the 1st millennium bc.