Seen from outside the old city wall, it is round. Step to the inside face and it becomes square. This is not a quirk of later rebuilding but a deliberate feature of its original design, documented in precise detail in a survey carried out in 1585 and recorded in the Calendar of Ancient Records of Dublin. Most people walking past have little idea they are looking at a fragment of a defensive circuit that once enclosed the entire medieval city.

The tower takes its name from James Stanihurst, recorder of Dublin, who owned the adjoining property, and the 1585 survey describes it with the kind of administrative thoroughness that makes a historian's day. A mural tower is, in simple terms, a tower built into or projecting from a town wall to allow defenders to cover the wall's outer face with flanking fire. This one stood to the east of the Pole Gate and was measured at three storeys high with three timber lofts, its walls six feet thick and the interior nineteen feet square, rising to forty-six feet above its base, with arrow loops on each floor. The survey also records the stretch of wall running from it toward the neighbouring Bremyngham's Tower, noting which sections were properly ramped and which still needed attention. The wall at that point stood twenty-eight feet high, with a rampier, or earthen backing, supporting much of its height. In the nineteenth century the tower was refaced, and it carries a pronounced base batter, the outward splaying of the wall's lower courses that adds stability and deflects projectiles.

The surviving remains sit on the north side of Ship Street, where an 85-metre stretch of the southern town wall still stands to a height of around five metres, running up to the Dublin Castle boundary. The wall is built of coursed masonry and leans outward slightly at street level because the road itself follows the line of the old fosse, the defensive ditch that once ran along the wall's outer face. The tower, still extant in modified form as of 2002, is most easily appreciated by walking along Ship Street Little and then comparing that external view with the interior face visible from within the castle grounds. The contrast in geometry is subtle but genuine, and once noticed, the 1585 surveyor's careful measurements start to feel less like dry bureaucracy and more like a working description of something still there to be read.