United Nations Regional Information Centre for Western Europe

United Nations Day for South–South Cooperation (International)

Battle of Saragarhi

Saragarhi Day (Sikhism)

National Day of Encouragement

National Day of Encouragement (United States)

Public holidays in Cape Verde

National Day (Cape Verde)

Nayrouz

Nayrouz (Coptic Orthodox Church) (leap years only, September 11 on normal years)

Enkutatash

Enkutatash falls on this day if it is a leap year. Celebrated on the first day of Mäskäräm. (Ethiopia, Eritrea, Rastafari)

Defenders Day (Maryland)

Defenders Day (Maryland, United States)

Day of Conception

Day of Conception (Russia)

Saint Patrick's Battalion

Commemoration of the mass hanging of the Saint Patrick's Battalion (Mexico)

September 12 (Eastern Orthodox liturgics)

Christian feast day:
September 12 (Eastern Orthodox liturgics)

Sacerdos of Lyon

Christian feast day:
Sacerdos of Lyon

Laisrén mac Nad Froích

Christian feast day:
Laisrén mac Nad Froích

John Henry Hobart

Christian feast day:
John Henry Hobart (Episcopal Church (USA))

Most Holy Name of the Blessed Virgin Mary

Christian feast day:
The Most Holy Name of the Blessed Virgin Mary

Guy of Anderlecht

Christian feast day:
Guy of Anderlecht