Jerbourg Point has a rich history of human habitation and defensive structures dating back to ancient times, including the Neolithic era, Bronze Age, and Middle Ages. Its strategic location has made it a site of historical significance.
Along the narrowest part of the Jerbourg promontory's isthmus, there are earthwork ramparts that were designed as a defensive camp or fortification. According to Gustave Jules Dupont in his 1870 work, "Histoire du Cotentin et de ses îles," these ramparts begin on the west side, at the top of the cliff, near the path leading from Petit-Port. There are three embankments, with the outermost one being the deepest, measuring about 8 feet (2.4 meters) in height. These embankments extend to the location of Doyles Monument. The three embankments are situated on the eastern slope, with the northern two positioned close to each other.
Numerous archaeological finds have been made in this area, including flint fragments, arrowheads, Celtic pottery, stone axes, grinding stones (müllers), and an unfinished double-headed stone hammer. A flint arrowhead from this site is now preserved in the Guy-Alles Museum.
Pottery has been discovered in various parts of Jerbourg Point, and the site has yielded stone tools, flint knives, and 10 arrowheads dating back to the Late Neolithic/Early Bronze Age period around 2000 B.C. These artifacts were found within the earthen ramparts that stretch from Portel Bay in the west to La Bate de Muir near Le Bie du Nez. The construction of the defensive ditch utilized a natural fault line in the narrowest part of the Djerburg Peninsula, which is approximately 400 meters wide at this location. The cliffs on both sides were steep enough that additional fortifications were not needed to protect the flanks. The ditch's base is situated on the cliff and is lined with stones bound together with clay.
Furthermore, a Roman hoard dating back to the late 3rd century was discovered in the 19th century at this site. This hoard contained 68 tetradrachms that were minted in Alexandria during the reigns of various emperors, including Probus (4 coins), Carus (3 coins), Numerian (3 coins), Carinus (4 coins), Diocletian (34 coins), and Maximian (19 coins). These coins provide valuable insights into the historical and economic connections of the area during the Roman period.
