The diocese now covers the modern ceremonial county of Cambridgeshire (excluding the Soke of Peterborough) and western Norfolk.

The diocese is ancient, and the area of Ely was part of the patrimony of Saint Etheldreda.

After her death in 679 she was buried outside the church, and her remains were later reburied inside, the foundress being commemorated as a great Anglian saint.

The Bishop of Peterborough has also been commissioned as assistant bishop in the diocese so that he can exercise pastoral care in several old Huntingdonshire parishes now within the Peterborough unitary authority: including Stanground, Orton, Woodston, Yaxley and Fletton.

[94] The chapelry of St Nicholas, Landwade, was also in this portion of the diocese until it was transferred to Suffolk.