File:Graffiti In Howth (4318750681).jpg

The name Howth is thought to be of Norse origin, perhaps being derived from the word Hoved ("head" in English). The Norwegians colonised the eastern shores of Ireland and built the city of Dublin as strategic base between Scandinavia and the Mediterranean. The Norse first invaded Howth in 819 and the surnames of some of the oldest families on the peninsula, such as Hartford, Thunder, Rickard and Waldron, are decedents of these early invaders.

After King Brian Boru's defeat of the Norse in 1014, many Norse fled to Howth to regroup and remain a force until their final defeat in Fingal in the middle of the 11th century. Howth still remained under the control of Irish and localized Norsemen until the invasion of Ireland by the Anglo-Normans in 1169.

Without the support of either the Irish or Scandinavians, Howth was isolated and fell to the Normans in 1177. One of the winning Normans, Armoricus (or Almeric) Tristam, was granted much of the land between the village and Sutton. Tristam took on the name of the saint on whose feast day the battle was won, and built his first castle near the harbour—and the St. Lawrence link remains even today, see Earl of Howth. The original title as Baron of Howth was granted to Almeric St. Lawrence by Henry II in 1181, for one knight's fee, one of the seven knight's fees of the superior overlordship of Fingal.