St Côme-du-Mont dominates the marshes of the Cotentin region, at the mouth of the Douve. In 950, a church dedicated to St Côme, was founded here. It was the seat of the only Cluniac priory in the Cotentin region. It is also the patronage of Cluny that explains the vast dimensions of the building which exceed the requirements of this rural parish. The church, which was built with courses of small stones, consists of a nave with three bays, aisles, transepts and a choir ending in a semi-circular apse.
Many aspects of the structure and sculpted decorations date from the 12th century: the porch and window of the west gable, the large arcades with round-headed arches, the single splay windows and all the capitals of the nave. A walled-up door in the south transept has set in it a sculpted tympanum. The chancel is decorated with a series of blind arches on its north wall. The semi-circular apse has a domed vault and is lit by three round-headed windows.
On the outside, one can observe flat buttresses on the western façade and east end, a corbel table and billets on the walls of the choir. A tower of square plan, of which the upper part was re-worked in the 15th century, dominates the entire church.