Traces of two marching camps have been found at the site. The larger camp, covering some 42 hectares (100 acres) was discovered in 1785 by Col. Alex Shand. A smaller camp, extending to 13 hectares (32 acres) and partially overlapping the area of the first, was discovered by J. K. St Joseph in 1968. This smaller camp predates the larger and has been dated to the campaigns of Agricola.
The site is situated at the headwaters of the River Ythan, where a series of natural springs supplies potable water, that was convenient for the large marching camp installed here by the Romans in the first few centuries AD.