Court tombs, which were built during the Neolithic period roughly five to six thousand years ago, take their name from the open, usually U-shaped forecourt that precedes the burial gallery. The forecourt is thought to have functioned as a ritual space for the living, a place of ceremony connected to the dead interred within. At Coolmurly, that court opens to the south-south-east, measuring at least 5.5 metres long and around 7.5 metres wide, and leads into a gallery running to a length of 9 metres.

The internal arrangement of the gallery is relatively legible despite the monument's overall state of wear. Two jambs, the upright stones that frame a doorway, mark the entrance, and three further pairs of jambs divide the interior into four chambers. A sillstone, a low threshold stone set across the floor between uprights, separates the second and third chambers. Both the gallery sides and the backstone at the far end remain largely in place, which is more than can be said for the long mound encasing the whole structure; that earthen covering, once perhaps considerably taller, now survives in a poorly preserved state measuring around 33 metres in length. Kerbstones, the edging stones that would originally have defined the mound's perimeter, are still visible in places, with seven probable examples exposed along the northern half of the western side. A further detail worth noting is the apparent remnant of a small lateral subsidiary chamber at the western side of the mound, set almost 5 metres beyond the rear of the main gallery, represented by a backstone and a southern sidestone still standing in position. A field fence now runs through the monument, cutting along both arms of the court and the eastern side of the gallery, and a small quarry sits just to the east of this fence behind the gallery, a reminder that working farmland and ancient remains have coexisted here for a long time, not always to the monument's advantage. The nearby wedge tomb, a different type of megalithic structure with a tapering roofed chamber, lies around 100 metres to the south-south-west, and the site of an unclassified megalithic tomb is recorded just 10 metres to the north.