The D-shaped cropmark, visible in photograph St. Joseph BDS 83, appears on what archaeologists describe as excellent agricultural land; a detail that hints at why this location was chosen by its original inhabitants centuries or perhaps millennia ago.

Cropmarks like this one form when buried archaeological features affect the growth of crops above them. Where ancient ditches once existed, crops grow taller and greener due to the deeper, moisture-retaining soil, whilst over buried walls or foundations, they remain stunted. From the air, these variations create distinctive patterns that reveal hidden histories beneath seemingly ordinary fields. The D-shaped form suggests this was likely a defended settlement or farmstead, with its curved side possibly facing inland for protection whilst the straight edge aligned with the lough shore.

This intriguing feature was documented as part of the Archaeological Survey of County Donegal, a comprehensive catalogue compiled by Brian Lacey and his team in 1983. The survey recorded field antiquities spanning from the Mesolithic period through to the 17th century, creating an invaluable record of Donegal's archaeological heritage. Though the exact date and purpose of the Ballybegly Little enclosure remain uncertain, its position on prime farmland overlooking Lough Swilly suggests it was home to a community that understood both the agricultural potential of the land and the strategic advantages of its waterside location.