Haidian District (simplified Chinese: 海淀区 (officially), 海甸区 (alternatively); traditional Chinese: 海淀區/海甸區; pinyin: Hǎidiàn Qū) is a suburban district of the municipality of Beijing. It lies towards the northwestern part of the urban core.
It is 431 square km in area, making it the second-largest district in urban Beijing (after Chaoyang), and is home to 2,240,124 inhabitants (2000 Census); however, in comparison to other districts, a higher percentage of its inhabitants do not have the governmental residential certificates for long-term residence, because Haidian District is where most universities are located and therefore many[quantify] of its inhabitants are college students. Its postal code is 100080.
Since the year 1992, Haidian District has signed official papers and established Sister City relationship with 14 cities and districts from 10 countries of 4 continents.