He was the author of more than three dozen books on New England history and folklore, as well as on scuba diving, shipwrecks and pirates.

The jails in Salem and Lawrence lacked toilets, which meant inmates had to defecate in buckets.

He found that all Essex County Sheriffs as far back as he could trace either died in office of heart problems or retired due to "an ailment of the blood".

Cahill was born and raised in Salem, Massachusetts and also wrote several auto-biographical books, one recounting his experiences as Sheriff, and another relating tales of his childhood growing up in New England during World War II.

Cahill's most widely distributed lore and histories are mostly in the form of small books that can still be found in large quantities within souvenir shops located at tourist attractions throughout New England.