Not lost in the sense of being overgrown or forgotten underfoot, but lost in the more bureaucratic sense of having no recorded identity beyond a single cartographic moment. What survives in the record for this County Dublin route is one line on one set of maps, labelled simply as the highway running from Dublin to Wicklow, and nothing more.

The maps in question come from the Down Survey of 1655 to 1656, one of the most ambitious land-mapping projects in Irish history. Commissioned by the Cromwellian administration to document confiscated Catholic-owned land for redistribution to soldiers and adventurers who had backed the parliamentary cause, the Down Survey was directed by William Petty and produced remarkably detailed maps of baronies and parishes across the country. Roads appeared on these maps not as subjects of interest in themselves but as incidental features, useful for orienting the viewer within the landscape. The highway from Dublin to Wicklow shows up in exactly that capacity, a line threading southward, named for its destination rather than for any place it passed through. Whether it followed the coast, cut inland through the hills, or took some intermediate route is not stated in the surviving notation.

For anyone curious enough to look into this, the Down Survey maps have been digitised and are accessible online through the Down Survey of Ireland project, which allows users to compare Petty's seventeenth-century baronial and parish maps against modern geography. Tracing what the highway might correspond to today is a matter of educated inference rather than certainty. The main road corridor between Dublin and Wicklow town has obviously existed in various forms for centuries, but matching a mid-seventeenth century line to a specific modern road requires caution. The interest here is less in locating the road precisely and more in what its bare presence on the map suggests: that by the 1650s, a recognised route south from the capital was well-established enough to warrant labelling, even if whoever drew the map saw no need to say anything further about it.