A field wall cuts across the southern to west-southwest stretch of the bank, a gap opens to the southwest, and a pit has been dug into the interior on the eastern side, its walls neatly faced with drystone-walling. Whatever it was originally, the monument has clearly been put to use more than once.

The earthwork is a rath, a type of ringfort that would once have enclosed a farmstead during the early medieval period, roughly between the fifth and twelfth centuries. These enclosures were typically defined by a raised bank, known as a rampart, and often by an outer ditch called a fosse. Here, a slight depression noted just outside the bank to the west may be the remnant of just such a fosse, though it survives only faintly. Thousands of ringforts are recorded across Ireland, making them among the most common field monuments in the country, yet each one carries its own particular history of use, neglect, and adaptation. At Boyhill, the pit cut into the interior is the most conspicuous alteration. A study by Cody in 1989 proposed that it was converted into an animal shelter at some point, its drystone-faced sides suggesting deliberate, if modest, construction work long after the original enclosure fell out of domestic use. The bank itself is best preserved along the western and northern arc, giving some sense of the scale and shape of what once stood here.