It was established by a decree of the Holy See dated 25 May 1927, when it was separated from the Calcutta Archdiocese to form a new Diocese, with its episcopal seat at Ranchi.

He traveled by bullock cart from Midnapur and after a difficult journey of a fortnight reached Chaibasa on 25 November 1868.

His work among the Ho tribe did not yield results, so he moved towards Ranchi district in January 1875.

To assist the missionaries, the Loreto Sisters from Ireland opened a convent in the red Lodge on Purulia Road, Ranchi, in March 1890.

As the faith spread and took firm root in Chotanagpur, the Catholic Church was being built up and developed, especially through parishes and schools.

On 19 September 1953, the Diocese of Ranchi was raised to the status of an Archdiocese with Sambalpur and Cuttack as its suffragans.

The Andamans and Nicobar Islands, became part of Ranchi in 1947, and were since 1966 under the care of the Pilar Fathers, and became a new Diocese on 26 June 1984.

[citation needed] The dioceses Daltonganj, Dumka, Gumla, Hazaribag, Jamshedpur, Khunti, Port Blair and Simdega are suffragans of the archdiocese.