The church design is notable for the great length of its chancel. Indeed it is only eleven feet shorter than the nave and of almost equal width. They are respectively fifty-one feet and sixty-two feet six inches long, thus forming a length of 113 feet.
St Mungo’s is the mother church of the North Tyne Valley. Up until the early 19th century, the original parish extended from Hadrian's Wall to Carter Bar and was at that time the largest parish in England; perhaps this helps to explain why the tiny village of Simonburn has such a large church.
There are traces of an Anglican church from the 9th century, but the present building is mainly 13th century in origin with sensitive restorations made in 1762 and 1863.
The Church of St Mungo is a grade II* listed building (
Link British Listed Buildings)
Link "The Great Parish of Simonburn" from Hadrian's Wall to Carter Bar
Link Northumbria.info
Link Wikipedia article about St Mungo