A mural tower, meaning a tower built into or projecting from a city wall rather than standing independently, it occupied the north-east corner of Dublin's medieval defences, where the River Poddle met the Liffey. The 1863 Ordnance Survey map had even placed the site roughly 40 metres from where it actually stood. When archaeologist Linzi Simpson excavated the spot that year, she found limestone courses surviving to about 2.5 metres on one side, walls nearly 4 metres thick, and the tower sitting directly on river gravels, its interior packed with silt, probably to stabilise the base against the water.

The tower's origins date to around 1260, when Dublin's city defences were extended outward across reclaimed land to reach the banks of the Liffey. It appears in the Dublin White Book in a grant to William Picot, Clerk of the City, which references the nearby Isolda's Gate, and the annual rent attached to a neighbouring tower was charmingly fixed at one pair of gilt spurs, payable to the Mayor each Easter Day. By 1585 a civic survey described the structure in careful detail: a round tower, two storeys high, 40 feet from the channel to its platform top, with walls 9 feet thick and three arrow loops in each room. It passed through several hands, including the Corporation of Bakers from 1558, before Jacob Newman took a lease in 1602, having petitioned the city to sue the bakers for the damage they had caused to it. The Dublin Assembly Roll records the slightly aggrieved tone of the city's response, noting that Newman could have had the key at any time he asked. On John Speed's 1610 map of Dublin it is marked as Newman's Tower, a name that stuck alongside the older Baker's Tower, though the older name, Isolde's Tower, is the one most often used today.

The conserved remains sit below ground level at the junction of Essex Quay and Lower Exchange Street, where the medieval wall line is followed by the modern street to the south. There is no great monument to find above the surface; the significance is almost entirely subsurface, and what is visible has been consolidated in place following the 1993 excavation. The finds from that dig, which included medieval and post-medieval pottery, glass, metal, leather, and human bones, suggest the site was in continuous use across several centuries before being demolished in the late seventeenth century and built over. Anyone passing the corner today, within sight of the Liffey and a short walk from the older sections of city wall near Cook Street, is standing at what was once the outermost north-eastern point of a walled medieval city, its edge quite literally in the river.