Hailar District (Mongolian: , Cyrillic: Хайлаар дүүрэг, Khailaar düüreg; ) is an urban district that serves as the seat of the prefecture-level city Hulunbuir in northeastern Inner Mongolia, People's Republic of China. Hulunbuir, due to its massive size, is a city in administrative terms only, being mainly grassland and rural. Hailar, therefore, is a de facto city. Hailar can also refer to the urban area around the Hailar district, with Hulunbuir being the wider geographical region that contains the urban area.