Posești is a commune in Prahova County, Muntenia, Romania. It is composed of ten villages: Bodești, Merdeala, Nucșoara de Jos, Nucșoara de Sus, Poseștii-Pământeni (the commune centre), Poseștii-Ungureni, Târlești, Valea Plopului, Valea Screzii, and Valea Stupinii. The commune is located in the northeastern part of the county, in the Sub Carpathian hills, on the border with Buzău County. It lies 16 km (9.9 mi) from Vălenii de Munte and 45 km (28 mi) from the county seat, Ploiești. Posești covers an area of 54.90 km2 (21.20 sq mi). The river Zeletin flows through the village Poseștii-Pământeni. According to the 2011 census, Posești has 3,990 inhabitants; 95.54% of them are ethnic Romanians and 1.36% are ethnic Romani. At the end of the 19th century, the commune was part of the Teleajenul plain of Prahova county, with the hamlets of Posești, Bodești and Valea Plopului. Râncezi commune was also organized on the current territory of the commune; it consisted of the villages of Râncezi (currently, Nucșoara de Jos) and Nucșoara (currently, Nucșoara de Sus); this commune had 1760 inhabitants, a school dating from 1880 and attended in 1899 by 70 students (of whom 18 were girls), and two Orthodox churches — two in Râncezi (one of which dates from 1840) and one in Nucșoara. Also at that time, the village of Târlești was the seat of a commune formed by it and the village of Gogesca, with a total of 1181 inhabitants, a school and an Orthodox church founded by the inhabitants in 1860. In 1925, the Socec Yearbook records the villages of Valea Screzii and Valea Stupinii in Posești commune, and the village of Posești divided into Poseștii Ungureni and Poseștii Pâmăteni, the whole commune having a population of 1932 inhabitants. In 1950, the communes of Târlești, Posești and Râncezi were transferred to the Teleajen district from the Prahova region and then (starting with 1952) from the Ploiești region. Râncezi commune (like her village of residence) was named Nucșoara de Jos in 1964. In 1968, the counties were re-established, but the commune of Nucșoara de Jos was abolished, being included in the commune of Posești, and the commune of Târlești was divided between the communes of Posești and Cărbunești.