Saint-Pierre-de-Plesguen

Mesnil-Roc'h (Breton: Sant-Pêr-Plewenn) is a commune in the Ille-et-Vilaine department in Brittany in northwestern France. It was established on 1 January 2019 by merger of the former communes of Saint-Pierre-de-Plesguen (the seat), Lanhélin and Tressé.

Plesder (Breton: Pleder) is a commune in the Ille-et-Vilaine department of Brittany in northwestern France.

Tressé (Breton: Trese, Gallo: Tresei) is a former commune in the Ille-et-Vilaine department of Brittany in northwestern metropolitan France. On 1 January 2019, it was merged into the new commune Mesnil-Roc'h.

Pleugueneuc (French pronunciation: [pløɡnøk]; Breton: Plegeneg; Gallo: Ploegenoec) is a commune in the Ille-et-Vilaine department in Brittany in northwestern France.

Saint-Hélen (French pronunciation: [sɛ̃.t‿elɛ̃]; Breton: Sant-Haelen) is a commune in the Côtes-d'Armor département of Brittany in northwestern France.

Les Champs-Géraux (French pronunciation: [le ʃɑ̃ ʒeʁo]; Breton: Maez-Geraod; Gallo: Lez Chaunt-Jéraud) is a commune in the Côtes-d'Armor department of Brittany in northwestern France.

Miniac-Morvan (French pronunciation: [minjak mɔʁvɑ̃]; Breton: Minieg-Morvan; Gallo: Meinyac-Morvan) is a commune in the Ille-et-Vilaine department in Brittany in northwestern France.

Pleudihen-sur-Rance (French pronunciation: [plødi.ɛ̃ syʁ ʁɑ̃s], literally Pleudihen on Rance; Breton: Pleudehen) is a commune in the Côtes-d'Armor department of Brittany in northwestern France. It is known for the production of apples and Breton champagne (cider). During the latter half of the 18th century, the town took in a large share of 2,000 Acadians who were deported to France against their will.

Trévérien (French pronunciation: [tʁeveʁjɛ̃]; Breton: Treverian) is a commune in the Ille-et-Vilaine department of Brittany in northwestern France.

La Vicomté-sur-Rance (French pronunciation: [la vikɔ̃te syʁ ʁɑ̃s], literally La Vicomté on Rance; Breton: Kerveskont) is a commune in the Côtes-d'Armor department of Brittany in northwestern France.

Saint-Domineuc (French pronunciation: [sɛ̃ dɔminøk]; Breton: Landoveneg) is a commune in the Ille-et-Vilaine département in Brittany in northwestern France.

Lanhélin (French pronunciation: [lɑ̃.elɛ̃]; Breton: Lanhelen) is a former commune in the Ille-et-Vilaine department in Brittany in northwestern France. On 1 January 2019, it was merged into the new commune Mesnil-Roc'h.