The Vilayets (Turkish pronunciation: [vilaːˈjet]) of the Ottoman Empire were the first-order administrative division, or provinces, of the later empire, introduced with the promulgation of the Vilayet Law (Turkish: Teşkil-i Vilayet Nizamnamesi) of 21 January 1867. The reform was part of the ongoing administrative reforms that were being enacted throughout the empire, and enshrined in the Imperial Edict of 1856. The reform was at first implemented experimentally in the Danube Vilayet, specially formed in 1864 and headed by the leading reformist Midhat Pasha. The reform was gradually implemented, and not until 1884 was it applied to the entirety of the Empire's provinces.
The term vilayet is derived from the Arabic word wilayah or wilaya. While in Arabic, the word wilaya is used to denote a province or region or district without any specific administrative connotation, the Ottomans used it to denote a specific administrative division.
The Ottoman Empire had already begun to modernize its administration and regularize its provinces (eyalets) in the 1840s, but the Vilayet Law extended this to the entire Ottoman territory, with a regularized hierarchy of administrative units: the vilayet, headed by a vali, was subdivided into sub-provinces (sanjak) under a mütesarrif, further into districts (kaza or liva) under a kaimakam, and into communes (nahiye) under a müdir.
The Six vilayets or Six provinces (Ottoman Turkish: ولايت سته Vilâyat-ı Sitte) or the Six Armenian vilayets (Armenian: Վեց հայկական վիլայեթներ Vets' haykakan vilayet'ner, Turkish: Altı vilayet, Altı Ermeni ili) were the Armenian-populated vilayets (provinces) of the Ottoman Empire:
The term Six Armenian provinces was first used in the Congress of Berlin in 1878.
Reliable population statistcs do not exist. Different versions are shown below.
Note: The analysis excludes certain portions of these provinces where the Armenians are only a minor element. These portions are as follows: Hakkari, in the Vilayet of Van; the south of Sairt, the Vilayet of Bitlis; the south of Vlayet of Diyarbekir; the south of Malatia, in the Vilayet of Mamouret-ul-Aziz; the north-west and west of the Vilayet of Sivas.
There is no evidence supporting the data of the Armenian Patriarch of Constantinople, as the methods of gathering of data was never cited. Also, the Patriarch had issued statistics of Six Vilayets in 1882 stating a total of 1.63 million Armenians in the area, 2.55 times the number they reached in the 1914 Census Report, but disowned 1882 figures in 1912 to publish new figures.