The Ţara (Ţara = Latin word for countries) are the most precisely defined zones. These are historic-social survivals from the Middle Ages and have evolved into ethnographical zones. Some of these zones are coexistent with the old medieval ţări (sing. = ţară, pl. = ţări) - which were sheltered along river valleys or in small depressions of the sub-mountain areas. The most pronounced geographical fragmentation is in Transylvania which gave a more precise delimiting of these ţări and regions into distinct units. The medieval names, dating from documents of the 14th to 18th centuries, are still used today for Ţara Bârsei, Ţara Oltului (or Ţara Făgăraşului), Ţara Zărandului, Ţara Moţilor, Ţara Bihariei, Ţara Lapuşului, Ţara Chioarului, Ţara Oaşului. Three further ţări are located outside Transylvania, but adjacent to the old borders of Transylvania; Ţara Dornelor, Ţara Vrancei are the only medieval ţări in Moldavia and Ţara Loviştei is the only ţara in Muntenia.
The term Ţinut ( = region) is used for the Moldavian ethnographic zones, such as Ţinutul Sucevei and Ţinutul Falticenului, and now also sometimes for some the Transylvanian zones. Another term occasionally used is ocol ( = district) which is common to the Slavic (Bulgarian = окòлия, Serbian = okolica). The same term was later used for the 1938-39 administrative regions.
Other areas are known as ethnographic entities without being specifically termed ţări. Examples of these are Mărginimea Sibiului, the Târnave and Năsăud regions, the Gurghiu valley, the source of the Mureş, Valea Almăjului, Valea Hârtibaciului, Valea Elanului. Some areas have simple names such as Codru and Pădureni.
East and south of the Carpathians the territorial units are larger and the boundaries between them are less well defined which gives rise to transitional areas. In these areas of Moldavia local ethnographic areas still exist such as - Neamţ, Roman, Huşi, Botoşani, Iaşi, Tutova hills, Valea Bistriţa, Valea Trotuş and Câmpulung Moldovenesc.
The term for the counties of Romanian (judeţ) originates from the 15th century where a judeţ was ruled by an administrative and judicial jude. The current system of administrative judeţ was created during the 19th century using the French departments system.
The zones south of the Carpathians, Buzău, Prahova, Vlaşca, Argeş, Muscel, Teleorman, Vâlcea, Gorj, Mehedinţi, are former historic regions which around 19th century were turned into administration units judeţ. Many of these also have sub-divisions corresponding to ethnographic zones.
There have been a number of changes to the administrative divisions which lead to variations in the region names in old ethnographic references. During 1927 to 1938 there were 71 judeţe. In 1938 King Carol II initiated an institutional reform resulting ten ţinuturi.
Initially the Communist party changed to the Russian raions, but reverted to the current judeţul in 1968, with minor changes creating counties of Giurgiu and Călăraşi in 1981.