Locally known as the Lisheen, it looks from a distance like a low circular earthwork, but the ground between its two rings of stone sits noticeably lower than the surrounding field, a consequence of the earth having been scooped from the interior to build up the banks themselves. That sunken corridor between the circles is one of the stranger sensations the site offers, a subtle but legible sign that whoever built this place was working to a deliberate and considered plan.

When T. C. Croker visited in 1833, he recorded it as the most intact of three stone circles then standing on Knockroe, noting a circumference of around 192 yards and two or possibly three rings of stone within the outermost one. By 1912, when Windle examined it more carefully, an earthen wall had been pushed through from east to west, and the eastern side had been considerably disturbed by later field boundaries. Windle counted thirty-three closely spaced stones in the inner circle, the tallest reaching about 1.2 metres, all of tabular limestone. He also noted a peculiar feature on the eastern side where the inner circle briefly splits into a double rank, forming a short pathway roughly ten metres in length. Excavations described by O'Kelly in 1944, and again in a 1978 survey by O'Kelly and O'Kelly, confirmed the presence of a ditch running inside the outer bank, an arrangement more typical of a henge, which is a type of ceremonial enclosure defined by a bank placed outside rather than inside its ditch, than a straightforward stone circle. No dateable finds were recovered, and the monument's age remains unknown. A pile of boulders thrown together without any clear arrangement was found in the north-eastern quadrant, its purpose equally unclear.

The site sits approximately twenty metres north-north-west of a small burial mound on Knockroe and is recorded as National Monument No. 247. The Loughgur area is unusually dense with prehistoric remains, so the Lisheen tends to receive less attention than the larger and more immediately legible monuments nearby. The double-ranked section on the eastern side of the inner circle is easy to miss, particularly where later disturbance has blurred the original stonework, but it is worth moving slowly around the inner ring to locate it. The low-lying ground between the two circuits is most apparent after rain, when the difference in level becomes easier to read.