In 2011, it had a population of 762,886 and thepopulation density was 161/km2. It is Romania's third most populated county (after the Municipality ofBucharest andIași County),[3] having a population density double that of the country's mean.
The area contains the mainoil reserves inRomania,[citation needed] with a longstanding tradition in extracting and refining the oil. The county is heavily industrialised, with over 115,000 residents working in industrial environments. It contributes to over 8% of the country's industrial production.[citation needed] Some of the biggest international corporations likeCoca-Cola,Unilever,InBev,Johnson Controls,Cameron,Weatherford,Michelin,Timken and others have invested heavily in the recent years.[citation needed]
The predominant industries in the county are:
Oil industry - almost 50% of the county's industrial production.
Oil extracting equipment.
Chemical industry.
Rubber industry.
Mechanical components industry.
Food and beverages industry.
Textile industry.
Agriculture is also developed — in the southern part mainly extensive agriculture and the hills area is well suited forwines and fruit orchards. In total it realises about 3% of the country's agricultural production.
Historically, the county was located in the south central part ofGreater Romania, in the central part of the historical region ofMuntenia. Its capital wasPloiești (then speltPloești). The interwar county territory comprised a large part of the current Prahova County, except the town ofMizil and several nearby villages that were then inBuzău County. In addition to the current county's territory, the interwar county contained several communes in its western part (includingDărmănești,I.L. Caragiale, andMoreni), currently inDâmbovița County, and some territory northwest ofPredeal, now inBrașov County.
According to the 1930 census data, the county population was 477,750 inhabitants, ethnically divided as follows: 95.0% Romanians, 1.5% Gypsies, 0.9% Jews, 0.8% Hungarians, 0.7% Germans, as well as other minorities.[8] From the religious point of view, the population was 96.0% Eastern Orthodox, 1.2% Roman Catholic, 1.0% Jewish, 0.6% Lutherans, 0.5% Greek Catholic, as well as other minorities.[9]
In 1930, the county's urban population was 105,098 inhabitants, comprising 88.8% Romanians, 3.5% Jews, 1.9% Hungarians, 1.7% Germans, 1.4% Romanies, as well as other minorities.[8] From the religious point of view, the urban population was composed of 89.2% Eastern Orthodox, 3.6% Jewish, 3.3% Roman Catholic, 1.5% Lutheran, 1.3% Greek Catholic, 0.6% Reformed, as well as other minorities.[9]