It was first mapped by Joseph Frederick Wallet Des Barres (1769 and 1776) and later by Admiral Henry Wolsey Bayfield (1837), where the name was recorded as Old Harry Head.

The toponym derives from Scotsman Harry Clarke, who was for many years the only occupant of the cape (or head).

Grosse-Ile and Entry Island are the two communities where English is the main language spoken, in the field and at sea, the age-old and daily exchanges have created and still create close relationships between the English- and French-speaking communities and individuals of the archipelago.

In 1972, the Société Québécoise d’Exploration Minière (SOQUEM)[9] discovered 7 salt domes,[10] including the one at Grosse-Île.

[12]'[13] The Pointe de l'Est National Wildlife Area is located on La Grosse Île, the reserve occupies an area of 748 hectares of the village of Grosse-Île territory's The hamlet of Old-Harry is located on the point of the same name, in the municipality of Grosse-Île, at the junction of Île de la Grande Entrée[broken anchor] and Île de l'Est.