The Diocese of Allahabad consists of the following twelve civil districts of Uttar Pradesh, viz., Allahabad, Ambedkar Nagar, Faizabad, Fatehpur, Kanpur City, Kanpur Dehat, (Akbarpur), Kaushambi, Mirzapur, Pratapgarh, Rae Bareli, Sonbhadra and Sultanpur.

The Diocese of Allahabad formerly one of the largest diocese in the world, since its erection in 1886, has contributed to form, entirely or partially, seven ecclesiastical units viz., the Archdiocese of Calcutta in 1887, the Diocese of Patna in 1919, the Prefecture of Jhansi in 1940, and the Prefecture of Gorakhpur in 1946. The last six divisions were made during the Episcopate of Bishop A. Poli ofm cap. The diocese was manned by the Capuchin Fathers of the Tuscany and Ancona Province till 1890, and by the Capuchin Fathers of the Bologna Province till 1947, when it was handed over to the Diocesan Clergy formed by Bishop A. Poli.