A squat, rendered cylinder of limestone rubble, it occupies the eastern quadrant of a coastal promontory fort, a prehistoric enclosure whose defensive earthworks predate it by roughly two millennia. The two monuments share a headland at Drumanagh Point, north of Rush in County Dublin, without any apparent acknowledgement of each other. A sunken roadway, still faintly traceable, runs from the southern end of the promontory fort's defences up to the tower's entrance, suggesting the older landscape was simply absorbed into the newer military infrastructure. The entrance itself is set above ground level on the western face and protected by machicolation, an overhanging gallery carried on stone corbels, through which defenders could drop stones or boiling water on anyone attempting to force the door.

The tower is designated No. 9 in the series of Martello towers built north of Dublin, a chain of twelve in total, each mounting a single 24-pounder cannon. Martello towers were squat, thick-walled circular fortifications developed in response to the threat of Napoleonic invasion; their name derives from a tower at Mortella Point in Corsica that had impressed British military observers. Construction of the Dublin towers began in 1804 under Colonel Benjamin Fisher of the Royal Engineers, and by December 1805 all were armed and complete. After the Napoleonic threat receded, the tower found a second life: by 1821 it was being used by the Preventive Water Guard to watch for smugglers along this stretch of coastline. The War Department took it back in 1855, and twelve rank and file troops were recorded as occupying it in 1857. It was disarmed by 1874, and in 1908 the War Department sold the tower to General Palmer of Kenure Park, Rush, for the sum of £50.

The tower sits in a field of pasture and is not openly accessible to the public; the promontory and surrounding land are privately held farmland. The structure is protected under a preservation order (PO no. 13/1977) made under the National Monuments Acts. Those visiting the Rush and Loughshinny area can observe the tower from a distance along the coastal fringe. The tower retains its corbelled stone roof and parapet coping, though the entrance door is long gone. A latrine structure survives to the east of the main tower. For anyone unable to visit in person, a 3D model of the tower has been made available online, which gives a reasonable sense of the building's compact geometry and the detail of the machicolation above the former doorway.