Changping District, formerly Changping County (昌平县), is a district situated in the suburbs of north and northwest Beijing. Changping has a population of 2,269,487 as of November 2020, making it the most populous suburban district of Beijing.

Line 5 of the Beijing Subway is Beijing's only subway line with an entirely north-south route. Line 5's color is maroon. It entered into operation on October 7, 2007. It runs for 27.6 km (17.1 mi) in a near straight line through the city center from Tiantongyuanbei in Changping District to Songjiazhuang in Fengtai District. Though Line 4 and Line 8 also broadly follow north-south routes, Line 5 remains the only line to follow an almost entirely straight north-south course. Line 5 is also notable for including three stations in the densely populated northern suburb of Tiantongyuan, as well as providing convenient access to the Temple of Earth and Temple of Heaven. Since Line 5 connects with Line 1, Line 2 (twice), Line 6, Line 7, Line 10 (twice), Line 13, Line 14 and Line 15, and also links densely populated suburbs directly to the city center, it tends to experience very crowded conditions during rush hour and even very late into the evening. Over 1 million passengers use the line every weekday in 2019.