Chittagong Division, officially known as Chattogram Division (Bengali: চট্টগ্রাম বিভাগ), is geographically the largest of the eight administrative divisions of Bangladesh. It covers the south-easternmost areas of the country, with a total area of 34,529.97 km (13,332.10 sq mi) and a population at the 2022 census of 33,202,326. The administrative division includes mainland Chittagong District, neighbouring districts and the Chittagong Hill Tracts.

Chittagong Division is home to Cox's Bazar, the longest natural sea beach in the world; as well as St. Martin's Island, Bangladesh's sole coral reef.

While the City of Chittagong and its coastal surroundings has history recorded back since Classical antiquity, the regional history of Chittagong division started its recorded factual data since the late antiquity. Northwestern Chittagong was once a historical region of Samatata with significant archeological medieval findings like Mainamati buddhist settlements ameliorated during the Deva dynasty period. The Chittagong Hill Tracts was a cluster of warring states clashed between vassals of Kingdom of Mrauk U and Twipra Kingdom. The Portuguese were the first europeans to be in contact in Chittagong region via building their trade post at Karnaphuli. Portugese settlement flourished in the region through trading and piracy accompanied by Kingdom of Mrauk U. Chittagong region was absorbed into Bengal Sultanate during mid-16th Century by Daud Khan Karrani ending the Portuguese influence at Bay of Bengal within 1666. While Chittagong and Cumilla amalgamated within Bengal Sultanate, the hill tracts remained buffered autonomous state between Chakma Kingdom and Kingdom of Mrauk U and eventually with the Mughal Empire as of 1666. On 1757 Bengal Subah was absorbed by East India Company, three years later the company sent Harry Verelst to succeed the Mughal Subedar Reza Khan. The Chakma monarch refused to recognize the company's hegemony over Bengal resulting encroachment on the Chittagong Hill Tracts by the company. In 1787 the hill tracts frontier was engrossed within East India Company and the then Raja Jan Baksh Khan of Chakman Kingdom pledged recognition upon British sovereignty in exchange for autonomous agenda.

The Chittagong as an administrative division was established in 1829 to serve as an administrative headquarters for five of Bengal's easternmost districts, with the Chittagong District serving as its headquarters. In East Pakistan, the division's Tippera district was renamed as Comilla District in 1960.

In 1984, fifteen districts were created by separating and reducing the original five districts of Chittagong, Comilla, Hill Tracts, Noakhali and Sylhet:

• The Chittagong District was divided into two districts; Chittagong and Cox's Bazar District
• The Comilla District was split into three districts; Comilla, Brahmanbaria and Chandpur
• The Hill Tracts District was split into three districts; Bandarban, Khagrachhari and Rangamati
• The Noakhali District was divided into three districts; Noakhali, Lakshmipur and Feni
• The Sylhet District was split into four districts; Sylhet, Habiganj, Moulvibazar and Sunamganj.

Sylhet, Habiganj, Moulvibazar and Sunamganj district ceded from the Chittagong Division to join a newly established Sylhet Division in 1995.

Chittagong Division is presently subdivided into eleven districts (zilas) and thence into 100 sub-districts (upazilas). The first six districts listed below comprise the north-western portion (37.6%) of the division, while the remaining five comprise the south-eastern portion (62.4%), the two portions being separated by the lower (or Bangladeshi) stretch of the Feni River; the upland districts of Khagrachhari, Rangamati and Bandarban together comprise that area previously known as the Chittagong Hill Tracts.

Districts

Name	Headquarters	Area (km)	Population 1991 Census	Population 2001 Census	Population 2011 Census	Population 2022 Census
Brahmanbaria District	Brahmanbaria	1,881.20	2,141,745	2,398,254	2,840,498	3,306,563
Comilla District	Comilla	3,146.30	4,032,666	4,595,539	5,387,288	6,212,216
Chandpur District	Chandpur	1,645.32	2,032,449	2,271,229	2,416,018	2,635,748
Lakshmipur District	Lakshmipur	1,440.39	1,312,337	1,489,901	1,729,188	1,938,111
Noakhali District	Maijdee	3,685.87	2,217,134	2,577,244	3,108,083	3,625,252
Feni District	Feni	990.36	1,096,745	1,240,384	1,437,371	1,648,896
Khagrachhari District	Khagrachhari	2,749.16	342,488	525,664	613,917	714,119
Rangamati District	Rangamati	6,116.11	401,388	508,182	595,979	647,587
Bandarban District	Bandarban	4,479.01	230,569	298,120	388,335	481,109
Chittagong District	Chittagong	5,282.92	5,296,127	6,612,140	7,616,352	9,169,464
Cox's Bazar District	Cox's Bazar	2,491.85	1,419,260	1,773,709	2,289,990	2,823,265
Total Districts	11	34,529.97	20,552,908	24,290,384	28,423,019	33,202,326

According to the 2022 Census of Bangladesh, Chittagong Division had 7,528,333 households and a population of 33,202,326, 33.7% of whom lived in urban areas. The population density was 979 people per km. 90.11% were Muslims, 6.61% Hindus, 2.92% Buddhists, 0.22% Christians and 0.14% others.

• Divisions of Bangladesh

• Government of Chittagong Division website