Demographics of Bihar Districts wise 
 District 
  
 Demographics 
 http://gov.bih.nic.in/Profile/Annexure-01.htm Population Distribution, Percentage Decadal Growth Rate, Sex-Ratio and Population Density

| Districts_of_Bihar | Total_Population_2001 | Male_Population_2001 | Female_Population_2001 | Growth_Rate_1981_91 | Growth_Rate_1991_01 | Sex_Ratio_1991 | Sex_Ratio_2001 | Population_density_1991 | Population_density_2001 |
|---|---|---|---|---|---|---|---|---|---|
| Katihar | 2389533 | 1244943 | 1144590 | 27.77 | 30.91 | 909 | 919 | 597 | 782 |
| Madhepura | 1524596 | 796272 | 728324 | 22.16 | 29.45 | 885 | 915 | 659 | 853 |
| Saharsa | 1506418 | 788585 | 717833 | 25.54 | 33.03 | 884 | 910 | 665 | 885 |
| Darbhanga | 3285473 | 1716640 | 1568833 | 25.04 | 30.85 | 911 | 914 | 1102 | 1442 |
| Muzaffarpur | 3743836 | 1941480 | 1802356 | 25.30 | 26.74 | 904 | 928 | 931 | 1180 |
| Gopalganj | 2149343 | 1072151 | 1077192 | 25.12 | 26.11 | 968 | 1005 | 838 | 1057 |
| Siwan district | 2708840 | 1332218 | 1376622 | 22.04 | 24.78 | 1017 | 1033 | 978 | 1221 |
| Saran | 3251474 | 1654428 | 1597046 | 23.44 | 26.37 | 963 | 965 | 974 | 1231 |
| Vaishali | 2712389 | 1412276 | 1300113 | 29.08 | 26.39 | 921 | 921 | 1054 | 1332 |
| Samastipur | 3413413 | 1771249 | 1642164 | 28.35 | 25.63 | 926 | 927 | 936 | 1175 |