Hailar District, formerly a county-level city, is an urban district that serves as the seat of the prefecture-level city Hulunbuir in northeastern Inner Mongolia, China. Hulunbuir, due to its massive size, is a city in administrative terms only, being mainly grassland and rural.

Hulunbuir or Hulun Buir is a region that is governed as a prefecture-level city in northeastern Inner Mongolia, China. Its administrative center is located at Hailar District, its largest urban area. Major scenic features are the high steppes of the Hulun Buir grasslands, the Hulun and Buir lakes, and the Khingan range. Hulun Buir borders Russia to the north and west, Mongolia to the south and west, Heilongjiang province to the east and Hinggan League to the direct south. Hulunbuir is a linguistically diverse area: next to Mandarin Chinese, Mongolian dialects such as Khorchin and Buryat, the Mongolic language Daur, and some Tungusic languages, including Oroqen and Solon, are spoken there.