Six vilayets
The Six vilayets or Six provinces or the Six Armenian vilayets were the Armenian-populated vilayets of the Ottoman Empire:
- Van
- Erzurum
- Mamuretülaziz
- Bitlis
- Diyarbekir
- Sivas
Term
Population
Ethnic groups
;Statistical analysis of the racial elements in the Ottoman provinces by the Armenian Patriarch of Constantinople, 1912Note: The analysis excludes certain portions of these provinces where Armenians are only a minor element. These portions are as follows: Hakkiari, in the Vilayet of Van; the south of Sairt, in the Vilayet of Bitlis; the south of the Vilayet of Diyarbekir; the south of Malatia, in the Vilayet of Mamuretülaziz; the north-west and west of the Vilayet of Sivas.
;Ottoman official population statistics, 1914
Note: The Ottoman population statistics doesn't give information for separate Muslim ethnic groups such as the Turks, Kurds, Circassians, etc.
The official Ottoman population statistics of 1914 that were based on an earlier census underestimated the number of ethnic minorities, including the number of Armenians. The Ottoman figures didn't define any ethnic groups, only religious ones. So the “Armenian” population as counted by the authorities only tallied ethnic Armenians who were also adherents of the Armenian Apostolic Church. Ethnic Armenians who professed the Muslim faith, which by that time had grown in number, were counted only as “Muslims”, while Armenian Protestants, just as Pontic Greeks, Caucasus Greeks, and Laz, were counted as "others".
| Ethnic groups | Bitlis | Diyarbekir | Erzurum | Mamuretülaziz | Sivas | Van | TOTAL | % |
| Muslims | 309,999 | 492,101 | 673,297 | 446,376 | 939,735 | 179,380 | 3,040,888 | 79.6 |
| Armenians | 119,132 | 65,850 | 136,618 | 87,862 | 151,674 | 67,792 | 628,928 | 16.5 |
| Others | 44,348 | 4,020 | 5,797 | 4,047 | 78,173 | 11,969 | 148,354 | 3.9 |
| TOTAL | 473,479 | 561,971 | 815,712 | 538,285 | 1,169,582 | 259,141 | 3,818,170 | 100 |
Largest cities
All figures are as of early 20th century.| City | Vilayet | Population | Armenians | % |
| Van | Van Vilayet | 40,000 | 25,000 | 62.5% |
| Sivas | Sivas Vilayet | 60,000 | 30,000 | 50% |
| Erzurum | Erzurum Vilayet | 60,000 | 15,000 | 25% |
| Mezereh | Vilayet of Mamuret-ul-Aziz | 12,00 | 6,000 | 50% |
| Bitlis | Bitlis Vilayet | 30,000 | 7,000 | 23% |
| Diyarbakır | Diyarbekir Vilayet | 15,000 | 45,000 | 33% |
| Arapgir | Vilayet of Mamuret-ul-Aziz | 20,000 | 10,000 | 50% |
| Malatya | Vilayet of Mamuret-ul-Aziz | 40,000 | 20,000 | 50% |