This stone burial chamber was recorded on a field map in 1995, though the structure itself dates back thousands of years to the Bronze Age, when such monuments were commonly constructed across the Irish landscape. The cist consists of a rectangular stone box, typically formed from four upright slabs with a capstone on top, designed to hold the remains of the deceased along with their grave goods.

These burial sites were carefully constructed by early farming communities who settled in Donegal's fertile valleys and coastal plains. The people who built this cist would have selected and transported heavy stone slabs, sometimes from considerable distances, to create a permanent resting place for their dead. Inside such chambers, archaeologists often find cremated remains placed in pottery vessels, along with items like flint tools, bronze implements, or decorative beads; objects meant to accompany the deceased into the afterlife.

The documentation of this site by Paul Walsh in April 2014 helps preserve knowledge of Ireland's archaeological heritage. While many cists have been discovered across Donegal, each one contributes to our understanding of Bronze Age burial practices and social structures. The Killygarvan Lower cist stands as a silent testament to the beliefs and customs of people who lived here long before written history began, their careful construction work surviving millennia of Irish weather and landscape changes.