Persians
Region: Central
Population: 50-60%
Language: Farsi
Provinces: Tehran, Isfahan, Fars, Alborz, Razavi Khorasan, South Khorasan, Yazd, Kerman, Bushehr, Hormozgan, Markazi, Qazvin, Gilan, Mazandaran, Semnan, Hamadan, North Khorasan, Khuzestan, half of Sistan & Baluchistan, southern and western half of Golestan.
Mazanderanis that speak Mazanderani, Tats, and Talysh fall under the Persian ethnic group.
Azeris
Region: North Western
Population: 16-20%
Language: Azerbaijani
Provinces: East Azerbaijan, West Azerbaijan, Ardabil, Zanjan, Qazvin, Hamadan
Violence has been escalating in some areas in this region, as the Islamic Republic security forces are stepping up their violent crackdown on protestors.
Kurds
Region: North Western
Population: 10%
Language: Kurdish
Provinces: West Azerbaijan, Kurdistan, Kermanshah, Ilam, parts of Hamadan, parts of Lorestan
22 year old Jina Mahsa Amini, whose death triggered the current wave of protests, is from this region. A convoy of heavy military vehicles with heavily armed troops have been spotted in this region and sounds of heavy weaponry have been heard on social media.
Lurs
Region: Western
Population: 6%
Language: Luri
Provinces: Lorestan, Chaharmahal & Bakhtiari, Khuzestan, Isfahan, Fars, Bushehr, Kohgiluyeh and Boyer-Ahmad
The funeral of 16 year old Nika Shakarami who was killed by the Islamic Republic was held in Khorramabad, Lorestan.
Gilaks
Region: Northern
Population: 4%
Language: Gilaki
Provinces: Mazandaran, Qazvin, Tehran, Alborz
The language is closely related to Mazanderani.
Arabs
Region: Southern
Population: 2%
Language: Arabic
Provinces: Khuzestan, Former Khorasan, Hormozgan, Bushehr, Qom
The province of Khuzestan is oil-rich and borders with Iraq.
Baloch
Region: Eastern
Population: 2%
Language: Balochi
Provinces: Sistan, Baluchistan
The region is the most isolated and remote area of Iran. On a day known as Bloody Friday, 93 people were killed by the security forces. This group has the highest casualties amongst the protestors.
Sources: irannegintravel.com, Wikipedia.org, University of Cologne