<P> A superintendent of Police, an officer belonging to Indian Police Service is entrusted with the responsibility of maintaining law and order and related issues . </P> <P> 3 to 5 districts comprise to form a division (प्रमंडल). Each district is divided into Sub-division (अनुमंडल), which are further sub-divided into C.D. Block (प्रखण्ड) </P> <Table> <Tr> <Td> Code </Td> <Td> District </Td> <Td> Headquarters </Td> <Td> Population (2011) </Td> <Td> Population (2001) </Td> <Td> Area (km2) </Td> <Td> Density (/ km2) (2001) </Td> </Tr> <Tr> <Td> AR </Td> <Td> Araria </Td> <Td> Araria </Td> <Td> 2,811,569 </Td> <Td> 2,124,831 </Td> <Td> 2,829 </Td> <Td> 751 </Td> <Td> </Td> </Tr> <Tr> <Td> AR </Td> <Td> Arwal </Td> <Td> Arwal </Td> <Td> 699,000 </Td> <Td> 589,476 </Td> <Td> 637 </Td> <Td> 918 </Td> <Td> </Td> </Tr> <Tr> <Td> AU </Td> <Td> Aurangabad </Td> <Td> Aurangabad </Td> <Td> 2,540,073 </Td> <Td> 2,004,960 </Td> <Td> 3,303 </Td> <Td> 607 </Td> <Td> </Td> </Tr> <Tr> <Td> BA </Td> <Td> Banka </Td> <Td> Banka </Td> <Td> 2,034,763 </Td> <Td> 1,608,778 </Td> <Td> 3,018 </Td> <Td> 533 </Td> <Td> </Td> </Tr> <Tr> <Td> BE </Td> <Td> Begusarai </Td> <Td> Begusarai </Td> <Td> 2,970,541 </Td> <Td> 2,342,989 </Td> <Td> 1,917 </Td> <Td> 1,222 </Td> <Td> </Td> </Tr> <Tr> <Td> BG </Td> <Td> Bhagalpur </Td> <Td> Bhagalpur </Td> <Td> 3,037,766 </Td> <Td> 2,430,331 </Td> <Td> 2,569 </Td> <Td> 946 </Td> <Td> </Td> </Tr> <Tr> <Td> BJ </Td> <Td> Bhojpur </Td> <Td> Arrah </Td> <Td> 2,728,407 </Td> <Td> 2,233,415 </Td> <Td> 2,473 </Td> <Td> 903 </Td> <Td> </Td> </Tr> <Tr> <Td> BU </Td> <Td> Buxar </Td> <Td> Buxar </Td> <Td> 1,706,352 </Td> <Td> 1,403,462 </Td> <Td> 1,624 </Td> <Td> 864 </Td> <Td> </Td> </Tr> <Tr> <Td> DA </Td> <Td> Darbhanga </Td> <Td> Darbhanga </Td> <Td> 3,937,385 </Td> <Td> 3,285,473 </Td> <Td> 2,278 </Td> <Td> 1,442 </Td> <Td> </Td> </Tr> <Tr> <Td> EC </Td> <Td> East Champaran </Td> <Td> Motihari </Td> <Td> 5,099,371 </Td> <Td> 3,933,636 </Td> <Td> 3,969 </Td> <Td> 991 </Td> <Td> </Td> </Tr> <Tr> <Td> GA </Td> <Td> Gaya </Td> <Td> Gaya </Td> <Td> 4,391,418 </Td> <Td> 3,464,983 </Td> <Td> 4,978 </Td> <Td> 696 </Td> <Td> </Td> </Tr> <Tr> <Td> GO </Td> <Td> Gopalganj </Td> <Td> Gopalganj </Td> <Td> 2,562,012 </Td> <Td> 2,149,343 </Td> <Td> 2,033 </Td> <Td> 1,057 </Td> <Td> </Td> </Tr> <Tr> <Td> JA </Td> <Td> Jamui </Td> <Td> Jamui </Td> <Td> 1,760,405 </Td> <Td> 1,397,474 </Td> <Td> 3,099 </Td> <Td> 451 </Td> <Td> </Td> </Tr> <Tr> <Td> JE </Td> <Td> Jehanabad </Td> <Td> Jehanabad </Td> <Td> 1,125,313 </Td> <Td> 924,839 </Td> <Td> 1,569 </Td> <Td> 963 </Td> <Td> </Td> </Tr> <Tr> <Td> KH </Td> <Td> Khagaria </Td> <Td> Khagaria </Td> <Td> 1,666,886 </Td> <Td> 1,276,677 </Td> <Td> 1,486 </Td> <Td> 859 </Td> <Td> </Td> </Tr> <Tr> <Td> KI </Td> <Td> Kishanganj </Td> <Td> Kishanganj </Td> <Td> 1,690,400 </Td> <Td> 1,294,063 </Td> <Td> 1,884 </Td> <Td> 687 </Td> <Td> </Td> </Tr> <Tr> <Td> KM </Td> <Td> Kaimur </Td> <Td> Bhabua </Td> <Td> 1,626,384 </Td> <Td> 1,284,575 </Td> <Td> 3,363 </Td> <Td> 382 </Td> <Td> </Td> </Tr> <Tr> <Td> KT </Td> <Td> Katihar </Td> <Td> Katihar </Td> <Td> 3,071,029 </Td> <Td> 2,389,533 </Td> <Td> 3,056 </Td> <Td> 782 </Td> <Td> </Td> </Tr> <Tr> <Td> LA </Td> <Td> Lakhisarai </Td> <Td> Lakhisarai </Td> <Td> 1,000,912 </Td> <Td> 801,173 </Td> <Td> 1,229 </Td> <Td> 652 </Td> <Td> </Td> </Tr> <Tr> <Td> MB </Td> <Td> Madhubani </Td> <Td> Madhubani </Td> <Td> 4,487,379 </Td> <Td> 3,570,651 </Td> <Td> 3,501 </Td> <Td> 1,020 </Td> <Td> </Td> </Tr> <Tr> <Td> MG </Td> <Td> Munger </Td> <Td> Munger </Td> <Td> 1,367,765 </Td> <Td> 1,135,499 </Td> <Td> 1,419 </Td> <Td> 800 </Td> <Td> </Td> </Tr> <Tr> <Td> MP </Td> <Td> Madhepura </Td> <Td> Madhepura </Td> <Td> 2,001,762 </Td> <Td> 1,524,596 </Td> <Td> 1,787 </Td> <Td> 853 </Td> <Td> </Td> </Tr> <Tr> <Td> MZ </Td> <Td> Muzaffarpur </Td> <Td> Muzaffarpur </Td> <Td> 4,801,062 </Td> <Td> 3,743,836 </Td> <Td> 3,173 </Td> <Td> 1,180 </Td> <Td> </Td> </Tr> <Tr> <Td> NL </Td> <Td> Nalanda </Td> <Td> Bihar Sharif </Td> <Td> 2,877,653 </Td> <Td> 2,368,327 </Td> <Td> 2,354 </Td> <Td> 1,006 </Td> <Td> </Td> </Tr> <Tr> <Td> NW </Td> <Td> Nawada </Td> <Td> Nawada </Td> <Td> 2,219,146 </Td> <Td> 1,809,425 </Td> <Td> 2,492 </Td> <Td> 726 </Td> <Td> </Td> </Tr> <Tr> <Td> PA </Td> <Td> Patna </Td> <Td> Patna </Td> <Td> 5,838,465 </Td> <Td> 4,709,851 </Td> <Td> 3,202 </Td> <Td> 1,471 </Td> <Td> </Td> </Tr> <Tr> <Td> PU </Td> <Td> Purnia </Td> <Td> Purnia </Td> <Td> 3,264,619 </Td> <Td> 2,540,788 </Td> <Td> 3,228 </Td> <Td> 787 </Td> <Td> </Td> </Tr> <Tr> <Td> RO </Td> <Td> Rohtas </Td> <Td> Sasaram </Td> <Td> 2,959,918 </Td> <Td> 2,448,762 </Td> <Td> 3,850 </Td> <Td> 636 </Td> <Td> </Td> </Tr> <Tr> <Td> SH </Td> <Td> Saharsa </Td> <Td> Saharsa </Td> <Td> 1,900,661 </Td> <Td> 1,506,418 </Td> <Td> 1,702 </Td> <Td> 885 </Td> <Td> </Td> </Tr> <Tr> <Td> SM </Td> <Td> Samastipur </Td> <Td> Samastipur </Td> <Td> 4,261,566 </Td> <Td> 3,413,413 </Td> <Td> 2,905 </Td> <Td> 1,175 </Td> <Td> </Td> </Tr> <Tr> <Td> SO </Td> <Td> Sheohar </Td> <Td> Sheohar </Td> <Td> 656,916 </Td> <Td> 514,288 </Td> <Td> 443 </Td> <Td> 1,161 </Td> <Td> </Td> </Tr> <Tr> <Td> SP </Td> <Td> Sheikhpura </Td> <Td> Sheikhpura </Td> <Td> 634,927 </Td> <Td> 525,137 </Td> <Td> 689 </Td> <Td> 762 </Td> <Td> </Td> </Tr> <Tr> <Td> SR </Td> <Td> Saran </Td> <Td> Chhapra </Td> <Td> 3,951,862 </Td> <Td> 3,251,474 </Td> <Td> 2,641 </Td> <Td> 1,231 </Td> <Td> </Td> </Tr> <Tr> <Td> ST </Td> <Td> Sitamarhi </Td> <Td> Dumra, Sitamarhi </Td> <Td> 3,423,574 </Td> <Td> 2,669,887 </Td> <Td> 2,199 </Td> <Td> 1,214 </Td> <Td> </Td> </Tr> <Tr> <Td> SU </Td> <Td> Supaul </Td> <Td> Supaul </Td> <Td> 2,229,076 </Td> <Td> 1,745,069 </Td> <Td> 2,410 </Td> <Td> 724 </Td> <Td> </Td> </Tr> <Tr> <Td> SW </Td> <Td> Siwan </Td> <Td> Siwan </Td> <Td> 3,330,464 </Td> <Td> 2,708,840 </Td> <Td> 2,219 </Td> <Td> 1,221 </Td> <Td> </Td> </Tr> <Tr> <Td> VA </Td> <Td> Vaishali </Td> <Td> Hajipur </Td> <Td> 3,495,021 </Td> <Td> 2,712,389 </Td> <Td> 2,036 </Td> <Td> 1,332 </Td> <Td> </Td> </Tr> <Tr> <Td> WC </Td> <Td> West Champaran </Td> <Td> Bettiah </Td> <Td> 3,935,042 </Td> <Td> 3,043,044 </Td> <Td> 5,229 </Td> <Td> 582 </Td> <Td> </Td> </Tr> </Table> <Tr> <Td> Code </Td> <Td> District </Td> <Td> Headquarters </Td> <Td> Population (2011) </Td> <Td> Population (2001) </Td> <Td> Area (km2) </Td> <Td> Density (/ km2) (2001) </Td> </Tr>

Which one is the largest district in bihar by area wise