The present church consists of a square-ended chancel and a nave with a S aisle and a S porch. Over the chancel arch is a double bellcote, and N of the chancel a vestry. It is thought that the lower courses of the N nave wall may be 12thc, but the church was re-built in the 13thc and again in the 14thc. There were 14thc, 15thc, 16thc and 17thc changes to the structure, and renovations were carried out in 1967 to 1973, including a vestry. The earliest surviving carved work in the church is the 12thc bowl of the baptismal font.

Domesday Book did not cover this part of England. The town of Dean, in Cumberland, was in the archdeaconry of Richmond, and was thus part of the diocese of York. Ranulph de Mechines was given this and other land in Cumbria in the late-11th or early-12thc, but on the death of the Earl of Chester in the White Ship disaster of 1120, he became the next Earl of Chester. Cumberland was subsequently divided, with Ranulph’s brother William given the southern section, which became the barony of Egremont. William granted a strip of land on the S bank of the Derwent to Waltheof/Waldeve, son of Gospatrick. This was to become the honour of Cockermouth, with its seat first in Papcastle and then Cockermouth. It contained the five towns/vills of Brigham, Eaglesfield, Dean, Greysouthen, and Clifton. Waltheof was also lord of the barony of Allerdale, but until the reign of Henry II, the Honour of Cockermouth remained dependent on the Barony of Egremont and not Allerdale. Under Henry II the two were assigned to Alicia and her husband Gilbert Pipard. The manor of Dean later passed through marriage to the Lucies and then the Percies. In the 16thc, Henry Percy, 6th Earl of Northumberland, granted it to Thomas Wharton, along with the advowson of the church, but after several generations it was purchased by the Earl of Egremont.

Dean is mentioned in relation to the appointment of Walthef as cleric of the chapel of Clifton sometime between 1161 and 1184. Before 1217, R., rector of the church of Dean, is mentioned in an inquisition concerning ‘Sorescal et Molkorkyn’. Thomas, rector of Dean, was also caught persuading inhabitants of the two Cliftons to bury their dead in his churchyard. This led to an investigation which was decided against him in 2019, after which he curtailed such efforts. In the Taxatio Ecclesiastica of 1291-92, the church of ‘Dene’ was rated at £22.13s.4d. The church was partially rebuilt and was re-dedicated /re-consecrated in 1447, apparently by a bishop of Dromore (Northern Ireland).

The baptismal font at Dean bears strong similarities to the font of Torpenhow’s church (Cumbria). A related font, with arcading of intersecting arches, survives in Hexham Priory church.