Swissair Flight 111 (SR111/SWR111) was a scheduled international passenger flight from John F. Kennedy International Airport in New York City, United States, to Cointrin Airport in Geneva, Switzerland. The flight was also a codeshare flight with Delta Air Lines. On 2 September 1998, the McDonnell Douglas MD-11 performing this flight, registration HB-IWF, crashed into the Atlantic Ocean southwest of Halifax Stanfield International Airport at the entrance to St. Margarets Bay, Nova Scotia. The crash site was 8 kilometres from shore, roughly equidistant from the small fishing and tourist communities of Peggy's Cove and Bayswater, killing all 229 passengers and crew on board the MD-11, making the crash the deadliest accident in the history of Swissair and the deadliest accident involving the McDonnell Douglas MD-11. It is also the second-deadliest aviation accident to occur in Canada, behind Arrow Air Flight 1285R.

Peggy's Cove is a small rural community located on the eastern shore of St. Margarets Bay in the Halifax Regional Municipality, which is the site of Peggys Cove Lighthouse.