Chhagalnaiya Upazila (Feni district) with an area of 133.49 sq km, is surrounded by Parshuram upazila on the north, Mirsharai upazila on the south, Indian State of Tripura on the east, Feni Sadar upazila on the west. 

Main rivers are Feni and Muhuri.

Chhagalnaiya (Town) consists of four mouzas. It has an area of 13.98 sq km. The town has a population of 21609; male 51.66% and female 48.34%; population density per sq km 1545. Literacy rate among the town people is 47.6%. The town has one dakbungalow. 

Administration Chhagalnaiya thana, now an upazila was established in 1872. The upazila consists of 6 union parishads, 54 mouzas and 63 villages.

Archaeological heritage and relics Shiluar Shil, Shuvapur Bridge, Banchpara Zamindar Bari and Sat Mandir (seven temple), remnants of the capital of Shamser Gazi, Kayara Dighi.

Historical events About 205 Hindu dwelling houses were ablazed, 45 persons were murdered and huge amounts of assets were plundered in a communal riot in January 1950.

Marks of the War of Liberation Memorial monument 2. Population 154116; male 49.79%, female 50.21%; Muslim 96.95%, Hindu 2.95% and others 0.1%.

Religious institutions Mosque 275, temple 10 and tomb 2, most noted of which are Chand Gazi Bhuiyan Mosque, South Ballavpur Mosque, Tomb of Panua Pir, Tomb of Roushan Fakir and Jagannath Mandir. 

Literacy and educational institutions Average literacy 43.10%; male 51.3% and female 36.6%. 

Educational institutions: college 5, high school 27, government primary school 61, non-government primary school 9, madrasa 29 and technical school 2. Noted educational institutions: Chhagalnaiya Government Primary School (1900), Chhagalnaiya High School (1915) and Joypur Sarojini High School (1917).

Locally published newspapers and periodicals Monthly Sagar Naiya and Monthly Haider; extinct- Weekly Aapil.Cultural organisations Public library 1, club 39, theatre group 1, women's organisation 1, music school 1, botanical garden 1 and playground 25.

Main occupations Agriculture 42.27%, agricultural labourer 7.64%, wage labourer 1.5%, industry 1.38%, transport 2.97%, landlord 4.02%, commerce 10.75%, service 17.05% and others 12.42%.

Land use Total cultivable land 10829 hectares; fallow land 50.58 hectares; single crop 15%, double crop 74% and treble crop land 11%; land under irrigation 70%.

Land control Among the peasants 8% are landless, 37% marginal, 30% small, 20% intermediate and 5% rich; cultivable land per head 0.15%.

Value of land The market value of the land of the first grade is approximately Taka 2500 per 0.01 hectare.

Main crops Paddy, potato, brinjal, chilli, pumpkin, bean, til and sugarcane Extinct or nearly extinct crops Tishi, kaun, tobacco and jute.

Main fruits Mango, jackfruit, banana, black berry, palm, pineapple and kul.Fisheries, dairies and poultries Fishery 1, dairy 3 and poultry 106.

Communication facilities Roads: pucca 60 km, semi pucca 35 km and mud road 412 km; waterways 9 nautical mile; railways 6.5 km.

Traditional transport Palanquin (extinct) and bullock cart (nearly extinct).

Manufactories Rice mill 132, saw mill 30, ice factory 1 and welding 35.

Cottage industries Goldsmith 53, blacksmith 44, potteries 15, wood work 170, sewing 310 and bamboo work 156. 

Hats, bazars and fairs Hats and bazars are 29, most noted of which are Koroiya Bazar, Daroga Bazar, Mirzar Bazar and Jamaddar Bazar etc; fair: 3, noted of which are Adhar Manik and Kaligachtola Mela. 

Main exports Paddy and wooden furniture. NGO activities Operationally important NGOs are Brac, ASA, Grameen Bank, CARE,, Swanirvar Bangladesh and LIFD. 

Health centres Upazila health complex 1, family planning centre 4, satellite clinic 3.