For the village in Constanța County, see Chirnogeni. For the village in Prahova County, see Dumbrăvești. For the village in Suceava County, see Salcea. For the village in Vaslui County, see Bogdana, Vaslui.
The town is situated at the northern edge of the Wallachian Plain, at an altitude of 240m (790ft), on the right bank of the Teleajen River. It is located in the central part of Prahova County, 15km (9.3mi) north of the county seat, Ploiești.
Plopeni is crossed by county road DJ102, which connects it to Păulești and Ploiești, where it meets national road DN1B. The Plopeni train station serves the CFRLine 306, which starts at Ploiești South station and ends in Slănic.