The Roman Catholic Diocese of Middlesbrough is a Latin Rite Roman Catholic diocese based in Middlesbrough, England and is part of the province of Liverpool. It was founded on 20 December 1878, with the splitting of the Diocese of Beverley which had covered all of Yorkshire. The modern day Middlesbrough diocese covers an area of 4,000 km² in North Yorkshire and the East Riding of Yorkshire, together with the City of York.