The Oak Island mystery is a series of stories and legends concerning buried treasure and unexplained objects found on or near Oak Island in Nova Scotia, Canada. As of 2025, the main treasure has not been found.^[1]

Since the 18th century, attempts have been made to find treasure and artifacts. Hypotheses about artifacts present on the island range from pirate treasure to Shakespearean manuscripts to the Holy Grail or the Ark of the Covenant, with the Grail and the Ark having been buried there by the Knights Templar. Various items have surfaced over the years that were found on the island, some of which have since been dated to be hundreds of years old.^[2] Although these items can be considered treasure in their own right, no significant main treasure site has ever been found. The site consists of digs by numerous individuals and groups of people. The original shaft, the location of which is unknown today, was dug by early explorers, and is known as "the money pit".

A "curse" on the treasure is said to have originated more than a century ago and states that seven men will die in the search for the treasure before it is found.^[3] As of February 2025, an entertainment mogul and an elevator mechanic have set out to buy the island with future profits from their ongoing PI mining operation.

Very little verified information is known about early treasure-related activities on Oak Island; thus, the following accounts are word of mouth stories reportedly going back to the late eighteenth century.^[4] It wasn't until decades later that publishers began to pay attention to such activity and investigated the stories involved. The earliest known story of a treasure found by a settler named Daniel McGinnis appeared in print in 1857. It then took another five years before one of the alleged original diggers gave a statement regarding the original story along with subsequent Onslow and Truro Company activities.

The original story by early settlers (first recorded in print in 1863) involves a dying sailor from the crew of Captain Kidd (d. 1701), in which he states that treasure worth £2 million had been buried on the island.^[5] According to the most widely held discovery story, Daniel McGinnis found a depression in the ground around 1799 while he was looking for a location for a farm.^[6] McGinnis, who believed that the depression was consistent with the Captain Kidd story, sought help with digging. With the assistance of two men identified only as John Smith and Anthony Vaughn, he excavated the depression and discovered a layer of flagstones two feet (61 cm) below.^[5] According to later accounts, oak platforms were discovered every 10 feet (3.0 m); however, the earliest accounts simply mention "marks" of some type at these intervals.^[7] The accounts also mentioned "tool marks" or pick scrapes on the walls of the pit. The earth was noticeably loose, not as hard-packed as the surrounding soil.^[7] The three men reportedly abandoned the excavation at 30 feet (9.1 m) due to "superstitious dread".^[8] Another twist on the story has all four people involved as teenagers. In this rendering McGinnis first finds the depression in 1795 while on a fishing expedition. The rest of the story is consistent with the first involving the logs found, but ends with all four individuals giving up after digging as much as they could.^[4][9][10]

In about 1802, a group known as the Onslow Company allegedly sailed from central Nova Scotia to Oak Island to recover what they believed to be hidden treasure.^[a] They continued the excavation down to about 90 feet (27 m), with layers of logs (or "marks") found about every ten feet (3.0 m), and also discovered layers of charcoal, putty and coconut fibre along with a large stone inscribed with symbols.^[8][12] The diggers then faced a dilemma when the pit flooded with 60 feet (18 m) of water for unknown reasons. The alleged excavation was eventually abandoned after workers attempted to recover the treasure from below by digging a tunnel from a second shaft that also flooded.^[11]

The last major company of the unpublished era was called The Truro Company, which was allegedly formed in 1849 by investors. The pit was re-excavated back down to the 86-foot (26 m) level, but ended up flooding again. It was then decided to drill five bore holes using a pod-auger into the original shaft. The auger passed through a spruce platform at 98 feet (30 m), then hit layers of oak, something described as "metal in pieces", another spruce layer, and clay for 7 feet (2.1 m).^[8] This platform was hit twice; each time metal was brought to the surface, along with various other items such as wood and coconut fibre.^[13]

Another shaft was then dug 109 feet (33 m) deep northwest of the original shaft, and a tunnel was again branched off in an attempt to intersect the treasure. Once again though, seawater flooded this new shaft; workers then assumed that the water was connected to the sea because the now-flooded new pit rose and fell with each tide cycle. The Truro Company shifted its resources to excavating a nearby cove known as "Smith's Cove" where they found a flood tunnel system.^[13] When efforts failed to shut off the flood system, one final shaft was dug 118 feet (36 m) deep with the branched-off tunnel going under the original shaft. Sometime during the excavation of this new shaft, the bottom of the original shaft collapsed. It was later speculated that the treasure had fallen through the new shaft into a deep void causing the new shaft to flood as well.^[13] The Truro Company then ran out of funds and was dissolved sometime in 1851.^[b]

The first published account took place in 1857, when the Liverpool Transcript mentioned a group digging for Captain Kidd's treasure on Oak Island.^[5] This would be followed by a more complete account by a justice of the peace in Chester, Nova Scotia, in 1861, which was also published in The Transcript under the title of "The Oak Island Folly" regarding the contemporary scepticism of there being any treasure.^[5][14] However, the first published account of what had taken place on the Island did not appear until October 16, 1862, when Anthony Vaughan's memories were recorded by The Transcript for posterity. Activities regarding the Onslow and Truro Companies were also included that mention the mysterious stone and the Truro owned auger hitting wooden platforms along with the "metal in pieces".^[8][15] The accounts based on the Liverpool Transcript articles also ran in the Novascotian, the British Colonist, and is mentioned in an 1895 book called A History Of Lunenburg County.^[16][17][18]