Bihar, a state of India, currently has 38 administrative districts, 101 subdivisions (अनुमंडल) and 534 CD blocks.

A district of an Indian state is an administrative geographical unit, headed by a district magistrate or a deputy commissioner, an officer belonging to the Indian Administrative Service. The district magistrate or the deputy commissioner is assisted by a number of officials belonging to different wings of the administrative services of the state.

A superintendent of police, an officer belonging to Indian Police Service, is entrusted with the responsibility of maintaining law and order and related issues.

3 to 6 districts are comprised to form a division (प्रमंडल). Each district is divided into sub-divisions (अनुमंडल), which are further sub-divided into CD blocks (प्रखण्ड).

List

#	Code	District	District Headquarters	C.D. Blocks	Population (2011)	Area (km2)	Density (/km2) (2011)	Map
1	AR	Araria	Araria	Araria Jokihat Kursakanta Raniganj Sikti Palasi Forbesganj Narpatganj Bhargama	2,811,569	2,829	751
2	AW	Arwal	Arwal	Arwal Kaler Karpi Kurtha Sonbhadra Banshi Suryapur	699,000	637	918
3	AU	Aurangabad	Aurangabad	Barun Navinagar Kutumba Madanpur Deo Rafiganj Obra Daudnagar Goh Haspura	2,540,073	3,303	607
4	BA	Banka	Banka	Amarpur Banka Barahat Belhar Bounsi Chandan Dhoraiya Fullidumar Katoriya Rajoun Sambhuganj	2,034,763	3,018	533
5	BE	Begusarai	Begusarai	Begusarai Barauni Teghra Matihani Bachhwara Mansurchak Naokothi Cheriabariyarpur Sahebpur Kamal Bakhari Birpur Dandari Garhpura Balia Chhorahi Khodawandpur Bhagwanpur Samho Akha Kurha	2,970,541	1,917	1,222
6	BG	Bhagalpur	Bhagalpur	Goradih Jagdishpur Nathnagar Sabour Shahkund Sultanganj Kahalgaon Pirpainti Sanhaula Bihpur Gopalpur Ismailpur Kharik Narayanpur Naugachhia Rangrachowk	3,037,766	2,569	946
7	BJ	Bhojpur	Arrah	Arrah Agiaon Barhara Koilwar Udwantnagar Sandesh Sahar Garhani Piro Charpokhari Tarari Jagdispur Bihiya Shahpur	2,728,407	2,473	903
8	BU	Buxar	Buxar	Buxar Itarhi Chausa Rajpur Dumraon Nawanagar Brahampur Kesath Chakki Chougain Simri	1,706,352	1,624	864
9	DA	Darbhanga	Darbhanga	Darbhanga Sadar Benipur Baheri Ali Nagar Hanuman Nagar Bahadurpur Hayaghat Keoti Singhwara Jale Manigachhi Tardih Biraul Ghanshyampur Kusheshwar Asthan Kusheshwar Asthan East Kiratpur Gaura Bauram	3,937,385	2,278	1,442
10	EC	East Champaran	Motihari	Raxaul Adapur Ramgarhwa Sugauli Banjaria Narkatia Bankatwa Ghorasahan Dhaka Chiraia Motihari Turkaulia Harsidhi Paharpur Areraj Sangrampur Kesaria Kalyanpur Kotwa Piprakothi Chakia Pakri Dayal Patahi Phenhara Madhuban Tetaria Mehsi	5,099,371	3,969	991
11	GA	Gaya	Gaya	Gaya Town Tikari Bodh Gaya Fatehpur Belaganj Wazirganj Konch Mohanpur Imamganj Gurua Khizirsarai Sherghati Dobhi Manpur Barachatti Guraru Banke Bazar Dumaria Tan Kuppa Amas Paraiya Muhra Neem Chak Bathani Atri	4,391,418	4,978	696
12	GO	Gopalganj	Gopalganj	Kuchaikote Barauli Hathua Gopalganj Baikunthpur Manjha Bhorey Uchkagaon Sidhwalia Bijaipur Katiya Phulwaria Thawe Pach Deuri	2,562,012	2,033	1,057
13	JA	Jamui	Jamui		1,760,405	3,099	451
14	JE	Jehanabad	Jehanabad	Makhdumpur Jehanabad Kako Ratni Faridpur Ghoshi Hulasganj Modanganj	1,125,313	1,569	963
15	KH	Khagaria	Khagaria	Alauli Khagaria Mansi Chautham Gogri Baldaur Parbatta	1,666,886	1,486	859
16	KI	Kishanganj	Kishanganj	Bhahadurganj Dighalbank Kishanganj Kochadhaman Pothia Terhagachha Thakurganj	1,690,400	1,884	687
17	KM	Kaimur	Bhabua	Bhabua Mohania	1,626,384	3,363	382
18	KT	Katihar	Katihar		3,071,029	3,056	782
19	LA	Lakhisarai	Lakhisarai		1,000,912	1,229	652
20	MB	Madhubani	Madhubani		4,487,379	3,501	1,020
21	MG	Munger	Munger		1,367,765	1,419	800
22	MP	Madhepura	Madhepura		2,001,762	1,787	853
23	MZ	Muzaffarpur	Muzaffarpur		4,801,062	3,173	1,180
24	NL	Nalanda	Bihar Sharif		2,877,653	2,354	1,006
25	NW	Nawada	Nawada	Akbarpur Govindpur Hisua Kashichak Kawakol Meskaur Nardiganj Narhat Nawada Pakribarawan Rajauli Roh Sirdala Warisaliganj	2,219,146	2,492	726
26	PA	Patna	Patna	Patna Sadar Sampatchak Phulwarisarif Fatwah Daniyawan Khusrupur Athmal gola Mokama Belchhi Ghoswari Pandarak Bakhtiyarpur Barh Masaurhi Punpun Dhanarua Danapur Maner Bihta Naubatpur Paliganj Dulhinbazar Bikram	5,838,465	3,202	1,471
27	PU	Purnia	Purnia	Purnia East Krityanand Nagar Kasba Srinagar Jalalgarh Banmankhi Dhamdaha Barhara Kothi Bhawanipur Rajdham Rupauli Dagarua Baisi Amour Baisa	3,264,619	3,228	787
28	RO	Rohtas	Sasaram		2,959,918	3,850	636
29	SH	Saharsa	Saharsa		1,900,661	1,702	885
30	SM	Samastipur	Samastipur	Tajpur Morwa Khanpur Sarairanjan Pusa Warishnagar Kalyanpur Rosera Hasanpur Bithan Shivajinagar Singhiya Bibhutipur Dalsingsarai Ujiyarpur Vidyapatinagar Patori Mohanpur Mohiuddin Nagar	4,261,566	2,905	1,175
31	SO	Sheohar	Sheohar		656,246	349	1,880
32	SP	Sheikhpura	Sheikhpura		634,927	689	762
33	SR	Saran	Chhapra	Amnour Baniapur Chhapra Dariyapur Dighwara Ekma Garkha Ishupur Jalalpur Lahladpur Maker Manjhi Marhaura Mashrakh Nagra Panapur Parsa Revelganj Sonpur Taraiya	3,951,862	2,641	1,231
34	ST	Sitamarhi	Dumra, Sitamarhi		3,423,574	2,199	1,214
35	SU	Supaul	Supaul		2,229,076	2,410	724
36	SW	Siwan	Siwan		3,330,464	2,219	1,221
37	VA	Vaishali	Hajipur		3,495,021	2,036	1,332
38	WC	West Champaran	Bettiah		3,935,042	5,229	582