The slave ship Mary left the African coast carrying enslaved Africans toward Saint Vincent and the Grenadines. About 224 people had been taken aboard.

Vessel: Mary; flag: Great Britain; rig: Brig; estimated standardized tonnage: 139. People recorded in connection with the voyage: Investor: Ingram, F; Investor: Butler, Chris; Captain: Rigby, James; Investor: Rigby, James. The voyage began at Liverpool on 7 May 1791. Principal recorded place where captives were acquired: Bight of Benin, place unspecified. Principal recorded disembarkation place: St Vincent, port unspecified. Estimated mortality during the crossing: 7.0%. Recorded outcome: Voyage completed as intended.