During the Irish Rebellion of 1641, Obins Castle was captured by a force of dispossessed Irish led by the McCanns, Magennises and O'Neills. In November 1641, Irish rebels—likely under the command of Toole McCann—killed about 100 captured British settlers by forcing them off the Bann bridge and shooting those who swam ashore. This became known as the "Portadown massacre" and was one of the worst atrocities of the rebellion. It fuelled revenge killings during the conflict that followed and was used to justify the Cromwellian conquest of Ireland. The Irish Confederate troops abandoned Obins Castle during the Cromwellian conquest, and Hamlet Obins (who had survived its capture) repossessed it in 1652. It was then passed to his son, Anthony Obins.