Known as Newhaven, it was once substantial enough to warrant its own customs station, to appear on Herman Moll's 1714 map of Dublin, and to be carefully illustrated, complete with pier and cluster of houses, on the Down Survey maps of the 1650s. What remains today lies underground, detectable only through geophysical survey, which has revealed a spread of archaeological activity across an area roughly 180 metres in extent, including dividing ditches, possible buildings or animal pens, and what appears to be a metalled trackway, a deliberately surfaced road, some 68 metres long and 8.5 metres wide.

The settlement's origins can be traced to sometime after 1562, when James Barnwell of Brymore and his wife Margaret were granted the right to establish a fisher town with a pier or harbour at Bremore. By 1592 it was appearing in historical records, and by 1607 documents were referring to it as 'le Horde alias le Newhaven of Brymore', suggesting a place with enough administrative weight to carry an alias. The Down Survey, a remarkable mid-seventeenth-century mapping project commissioned under Cromwellian rule to catalogue Irish landholdings, described it as a secure harbour made through the industry of its inhabitants, and noted it was a considerable place for fishing. The Civil Survey of the same period names the proprietor as Matthew Barnewall of Bremore, described as an Irish Papist, and records ten small cottages at Newhaven. The 1659 census puts the population at 34 people. By 1684 a customs station had been established there to monitor the coast and check the illegal movement of goods, which suggests the harbour was busy enough, or remote enough, to attract that kind of trade. The Hearth Money Rolls, a tax record based on the number of fireplaces in each dwelling, list nine houses, each with a single hearth.

The site sits on Bremore headland in north County Dublin, close to Balbriggan. Because the settlement has no surface expression, there is little to see without knowing what to look for, though the coastal setting itself retains something of the character that would have made a small harbour viable here. The geophysical survey results, published under licence number 06R0050, suggest that the buried remains include burgage plots, the long narrow property divisions typical of medieval planned towns, opening southward onto that metalled trackway. Visiting in clear weather when the low sun throws the ground into relief is worth the effort, as earthwork traces, if any survive, are easiest to read in those conditions. The primary record of what Newhaven looked like remains the barony maps held by the Royal Society of Antiquaries of Ireland, where the pier and five small houses are drawn with a directness that no later map would bother to replicate.