Cosmina de Jos is a village located within the commune of Cosminele in Prahova County, situated in the Muntenia region of Romania. It serves as one of the four constituent villages that make up the administrative boundaries of the Cosminele commune.
The area is defined by its rural character and its inclusion in the local governance structure alongside the neighboring villages of Cosmina de Sus, Drăghicești, and Poiana Trestiei.