The Irish form, Lios an tSidheáin, was translated as 'Fairy Hill' in the Ordnance Survey Letters of 1839, and the name stuck: it appears on both the 1842 and 1920 editions of the six-inch Ordnance Survey map, hachured and labelled, suggesting the site was locally conspicuous long after its original purpose had been forgotten. A rath is an earthen ringfort, typically the enclosed farmstead of an early medieval family, though sites like this one, elevated and visually commanding, often accumulated other associations over time.

What makes Lissateeaun genuinely unusual is the question of how much of it is human work and how much is simply geology pressed into service. The rath is subtriangular in plan, measuring roughly 36.7 metres east to west and 27 metres north to south, and its southern and western sides are defined by a steep natural-looking scarp rather than a built-up bank. Along the southern edge runs a deep, round-bottomed fosse, a defensive ditch, some four to six metres wide, dropping seven metres below the summit platform and two metres below the surrounding ground level. T. J. Westropp, writing in 1915, concluded that the site had been 'shaped out of the natural bluff, but raised and rounded so as to form a high flat-topped platform sufficiently imposing as seen from the road bridge to the east.' The scarp itself may be largely natural; the builders appear to have recognised what the hill already offered and enhanced it rather than constructing from scratch. There is a slight berm, a narrow ledge partway down the slope, on the northern, south-eastern, and south-western sides, and faint traces of a possible outer bank to the north-north-east. To the north, the site overlooks an extensive field system that spans multiple periods, suggesting this corner of Clare was worked and inhabited across a long span of time.