Knockmealdown, Mountain summit in County Waterford, Ireland.

Knockmealdown is a mountain summit in County Waterford, southeast Ireland, forming the natural boundary between Waterford and County Tipperary along its ridge. It is the highest point in the Knockmealdown Mountains, a range that runs roughly east to west across the region.

The Knockmealdown range has been crossed by travellers and traders for centuries, with old routes linking the lowlands of Waterford to the plains of Tipperary through the mountain passes. The Irish name of the peak appears in early written sources, pointing to how long this landscape has carried a fixed identity in the local memory.

The name is the anglicised form of the Irish Cnoc Mhaoldomhnaigh, usually understood as "Muldowneys' hill"; a rival reading is Cnoc Maol Donn, "bald brown hill". A 1654 record spells it Knockmealdowny, with an extra final syllable. The summit line also carries the county boundary, so walkers pass between Waterford and Tipperary on the ridge.

The usual approach from the west starts at the layby above Bay Lough on the Vee Gap, but this route first climbs Sugarloaf Hill. A second option follows the Glannandaree stream from the carpark where the R668 and R669 meet. The ground is open and exposed, so bring boots and waterproof layers.

The summit lies on the county boundary, and the ridge marks the highest ground in County Waterford at 794 metres. Walkers coming from the west via the Vee Gap layby first climb Sugarloaf Hill before reaching the top, so the final approach follows the county line itself.