Plélan-le-Petit comes from the Breton "plou" (parish) and "lann" (hermitage).
Plélan is an old primitive parish which once encompassed besides the present territory of Plélan-le-Petit, those of La Landec, Trébédan, Mégrit, Languédias, Trédias (Saint Urielle), Saint-Meloir-close-Bourseul (southern half).
Plélan name appears only in 1330 and the church is a cure-priory of Beaulieu Abbey until the Revolution. Under the Old Regime, Plélan is a parish of the diocese of Saint-Malo and Saint-Michel de Plélan branch. The old parish Plélan-le-Petit depended on the delegate and spring Dinan. The cure was presented by the Abbot of Beauport. Plélan-le-Petit elects its first municipality in early 1790. The term "-le-Petit" was added in 1790 to distinguish the town from that of Plélan-le-Grand (Ille-et-Vilaine).
By a decree of 17 July 1805 the territory of the parish rectory Plélan-le-Petit is increased by the territory of Saint-Michel-de-Plélan, formerly part of the branch of St. Maudez, suppressed by the same decree; at the same time is reduced by that of the new branch Languédias, erected by the same decree. By order of 17 May 1826, the territory of the parish parsonage is reduced by Saint-Michel, who met in Saint-Méloir erected in store by the same order.
You meet the following names: Eccl. Plelan (1330), Plelan near Dinan (in 1490), Plelan le Petit (fifteenth century).