Plogonnec (Breton: Plogoneg) is a commune and small town in the Finistère department of Brittany in north-western France. It is about 13 km (8 mi) north west of Quimper and 10 km (6 mi) east of Douarnenez. The town is twinned with Llandysul in Wales.
The town is situated in a hilly area about 10 km (6 mi) inland from the fishing port of Douarnenez. Quimper is about 15 km (9 mi) to the south east and the N165 Brest to Nantes trunk road lies between Plogonnec and Quimper. The lowest part of the commune is the River Névet, the town is at an altitude of 130 m (427 ft) and the commune rises in the north to an altitude of 286 m (938 ft) on the slopes of the Montagne de Locronan. Panoramic views to the coast are available from the Montagne du Prieuré. The total area of the commune is around 3,200 ha (7,900 acres). Much of the land is agricultural but there are several protected areas of woodland. To the west is the extensive Bois du Nevet which offers opportunities for hiking.