The Pittsburgh riot was a 19th-century race riot in which an armed clash between Irish American and Italian-American laborers resulted in one man seriously injured and the death of another on September 19, 1886. During the mid-1880s, relations between Irish-Americans and Italian-Americans had been steadily worsening, as the Italians had for some time been encroaching the working-class neighborhood of Four Mile Run in the 15th Ward of Pittsburgh, Pennsylvania. Five Italians were arrested in connection to the riots, although the unidentified Irish rioters were never apprehended.