Maharaja Sir Rajendra Narayan Singh Deo KCIE (31 March 1912 – 23 February 1975) was an Indian politician and the last ruler of the princely state of Patna in Odisha before Indian independence in 1947.
He was the President of the Ganatantra Parishad political party from 1950 to 1962 and the President of the Odisha state unit of the Swatantra Party after its merger with the Ganatantra Parishad in 1962. He was the Chief Minister of Odisha from 1967 to 1971.
Rajendra Narayan Singh Deo was born to Raja Aditya Pratap Singh, the ruler of the princely state of Seraikela and Rani Padmini Kumari Devi. He was adopted by Maharaja Prithwiraj Singh Deo of Patna state. He studied in the Mayo College in Ajmer and the St. Columbia’s College in Hazaribagh.
He became the Maharaja of Patna state in 1924 and assumed full powers in 1933. He was appointed a Knight Commander of the Order of the Indian Empire in the 1946 New Year Honours list. In 1948, the princely state of Patna was merged with the Union of India.