Udham Singh (26 December 1899 – 31 July 1940) was an Indian revolutionary best known for assassinating Michael O'Dwyer on 13 March 1940 in what has been described as an avenging of the Jallianwalla Bagh Massacre. Singh is a prominent figure of the Indian independence struggle. He is sometimes referred to as Shaheed-i-Azam Sardar Udham Singh (the expression "Shaheed-i-Azam," Urdu: شهید اعظم‎, means "the great martyr"). A district (Udham Singh Nagar) of Uttarakhand is named after him.