About the Castonguay surname
The surname Castonguay has an onomastic interpretation that still needs to be placed in the history of each family line. The form of Castonguay is compatible with French surname tradition. It may derive from an old given name, a place, a nickname, or an occupation; without a documented historical form, choosing a single explanation would be premature. This interpretation helps explain the formation of the surname without establishing the origin of any particular family line. The etymological interpretation should be compared with the earliest spellings and places associated with each family line.
Pronunciation:
Kas-ton-gouè/kastɔ̃ɡuɛ/