Until 1990, the province was known as Bovir Ahmadi and Kohkiluyeh.[2] Kurdistan Sanandaj 29,137 km2 (11,250 sq mi) 1,603,011 51.3/km2 (133/sq mi) 9 70.6 74.1 Originally part of Gilan province.[2] Lorestan Khorramabad 28,294 km2 (10,924 sq mi) 1,760,649 62.0/km2 (161/sq mi) 9 71.1 74.5 Originally part of Khuzestan province.[2] Markazi Arak 29,130 km2 (11,250 sq mi) 1,429,475 48.5/km2 (126/sq mi) 10 72.9 76.7 Originally part of Mazandaran province.[2] In 1986, some parts of Markazi province were transferred to Isfahan, Semnan, and Zanjan provinces.[2] Mazandaran Sari 23,701 km2 (9,151 sq mi) 3,283,582 129.7/km2 (336/sq mi) 15 73.5 77 Qazvin Qazvin 15,549 km2 (6,004 sq mi) 1,273,761 77.3/km2 (200/sq mi) 5 71.8 75.3 On 31 December 1996, the shahrestans of Qazvin and Takestan were separated from Zanjan province to form the province of Qazvin.[2] Qom Qom 11,526 km2 (4,450 sq mi) 1,292,283 99.9/km2 (259/sq mi) 1 71.5 75.6 Until 1995, Qom was a shahrestan of Tehran province.[2] Semnan Semnan 97,491 km2 (37,641 sq mi) 702,360 6.5/km2 (17/sq mi) 4 73.2 76.1 Originally part of Mazandaran province.[2] In 1986, some parts of Markazi province were transferred to Isfahan, Semnan, and Zanjan provinces.[2] Sistan and Baluchestan Zahedan 180,726 km2 (69,779 sq mi) 2,775,014 13.9/km2 (36/sq mi) 8 65.7 69.2 Until 1986, the province was known as Baluchestan and Sistan.[2] Tehran Tehran 18,814 km2 (7,264 sq mi) 13,267,637 647.6/km2 (1,677/sq mi) 13 74.3 77.8 Until 1986, Tehran was part of Markazi province.