In archaeology, a ring ditch is a trench of circular or penannular plan, cut into bedrock.
The term is most often used as a generic description in cases where there is no clear evidence for the function of the site: for instance where it has been ploughed flat and is known only as a cropmark or a geophysical anomaly.
The two most frequent monument types represented by ring ditches are roundhouses (where the 'ditch' is actually a foundation slot or eaves drip gully) and round barrows.
Found in eastern Bolivia, the pre-Columbian ring ditches have often been interpreted as evidence of cultural development and population movement in Amazonian archaeology.
One such project, centered on Santa Ana del Yacuma (near the Yacuma River) used the following methods to measure and record ring ditches: First, ASTER, Advanced Spaceborne Thermal Emission and Reflection Radiometer, was used in combination with GPS data to help guide field survey.
The structures resemble the size and shape those of the well known Neolithic ring-ditches from Slovakia, Austria, Southern Bavaria and England.