Surviving towers range in height from to , and to in circumference; that at Kilmacduagh being the highest surviving in Ireland (and leaning out of perpendicular). The masonry differs according to date, the earliest examples being uncut rubble, while the later ones are of neatly joined stonework (ashlar). The lower portion is solid masonry with a single door raised two to three metres above, often accessible only by a ladder. Within, in some, are two or more floors (or signs of where such floors existed), usually of wood, and it is thought that there were ladders in between. The windows, which are high up, are slits in the stone. The cap (roof), is of stone, usually conical in shape, although some of the towers are now crowned by a later circle of battlements.