New Orleans massacre of 1866, incident of white violence directed against newly freed African Americans in urban New Orleans, Louisiana, after the end of the American Civil War. On July 30, 1866, a mob of white men—acting with the compliance and even aid of local civilian authorities and the police—killed 35 Black citizens and wounded more than 100 who had gathered peacefully to support a political meeting at the New Orleans Mechanics Institute. This horrific event, which was proceeded by the Memphis massacre just a few months earlier, and the establishment of the highly restrictive black codes, helped focus public opinion in the North on the necessity of taking firmer measures to oversee Reconstruction, and ultimately provided a commanding win for the Radical Republicans and their vigorous Reconstruction policies in the November 1866 national elections.