There are twelve administrative divisions in Phnom Penh. Longbian District is one of the four administrative districts in the urban area. Longbian District is located on the northeast side of the urban area, the first quadrant of the central axis of Phnom Penh, east of Monivong Avenue, north of Sihanoukville Avenue, and west of Tonle Sap River, covering an area of about 7.44 square kilometres. Longbian District is the earliest developed area in Phnom Penh, with three markets-Old Street Market, Qianlong Street and New Street Market. The most famous Royal Palace, Zhen La Theater, Central Market, Ta Tsai Mountain and Old Night Market are all included. Like the neighbouring BKK District, Long Bien District represents the most prosperous economic centre of Phnom Penh.