About the Heffernan surname
The modern spelling of Heffernan alone is not enough to establish a certain origin. The canonical form used here is “Heffernan”; phonetic or spelling differences found in indexes should be checked against the other information in the record. Migration, language shifts, and record transcription can alter a surname over successive generations.
Pronunciation:
È-fèr-nan/ɛfɛʁnɑ̃/