Margashirsha month (Margasheersh, Margashira, Margasira masam), is the ninth month as per traditional North Indian Hindi Hindu calendar. Margashirsha month 2012-2013 starts on November 29 and ends on December 28 according to North Indian traditional Hindi Hindu calendar followed in Uttar Pradesh, Madhya Pradesh, Bihar, Jharkhand, Chhattisgarh, Himachal Pradesh, etc.
In other calendars like Marathi, Gujarati, Telugu and Kannada calendars, Margashira month 2012-2013 starts on December 14, 2012 and ends on January 11, 2013.
During Margashira month Mrigasira nakshatra or Mrugashira star falls near Purnima day. Due to that this month is named as Margashirsh. This month is an auspicious month to perform Shiva puja, Vishnu puja, Dattatreya puja and Hanuman Puja.
As per Bengali calendar, Margashirsh month is also called as Agrahayana or Agrahayon. Margashirsh is the second month as per traditional Gujarati calendar.