September 12 is the 255th day of the year (256th in leap years) in the Gregorian calendar. There are 110 days remaining.

Deaths

RC Saints - Holy Name of Mary, Sacerdos of Lyon, Guy of Anderlecht
Also see September 12 (Eastern Orthodox liturgics).
Cape Verde - National Day.
Ethiopia - National Revolution Day (1974).
Maryland (United States) - Defenders Day.
Mexico - Commemoration of the mass hanging of the Saint Patrick's Battalion.