This Ecclesiastical Unit was created as an Apostolic Exarchate on March 23, 1972 by the Papal Bull 'Beatorum Apostolorum' and entrusted to the Sacred Heart Province of the Carmelites of Mary Immaculate. The area comprising the diocese was culled out from the Diocese of Meerut. It consists of the district of Bijnor, except Dhampur division, and the five hill districts of Pauri-Garhwal, Rudraprayag, Tehri, Chamoli, Uttarkashi and a portion of the district of Haridwar.

Bp Gratian Muddadan, cmi, was nominated as its first Apostolic Exarch.

On February 26, 1977 the Papal Bull 'Quae cum Romano Pontificatu' of Pope Paul VI raised the Apostolic Exarchate to a diocese, Msgr Gratian Mundadan, cmi, was appointed its First Bishop.