The diocese comprises the whole of the City of Sheffield, and the surrounding towns of Rotherham, Doncaster, Barnsley, Chesterfield, the Peak District and areas of Worksop and Retford.

[1] It is a suffragan diocese in the ecclesiastical province of the metropolitan Archdiocese of Liverpool.

It is under the patronage of Our Lady of Perpetual Succour, whose feast is celebrated as a solemnity in the diocese on 27 June.

The first Bishop of Hallam was Gerald Moverley, who resigned in July 1996 and died later that year.

The third and current incumbent is Ralph Heskett, C.Ss.R., who had previously been Bishop of Gibraltar.