Salzgitter (German pronunciation: [zaltsˈɡɪtɐ] ; Eastphalian: Soltgitter) is an independent city in southeast Lower Saxony, Germany, located between Hildesheim and Braunschweig. Together with Wolfsburg and Braunschweig, Salzgitter is one of the seven Oberzentren (metropolitan areas) of Lower Saxony. With 107,674 inhabitants and 223.92 square kilometres (86.46 sq mi) (as of 2015), it is the largest city by area in Lower Saxony and one of the largest in Germany. Salzgitter originated as a conglomeration of several small towns and villages, and is today made up of 31 boroughs, which are relatively compact conurbations with wide stretches of open country between them.
The city is part of two urban areas, Hildesheim and Braunschweig, because of its uneven distribution of urban quarters. Due to the uneven population distribution, the density of the areas within the Braunschweig urban area is over 1,500 people per km² with the Lebenstedt area having over 3,000 people per km². Over 70% (76,500) of the population lives within the urban area of Braunschweig, but most of the area is within the urban area of Hildesheim. 54.1% (41,000 people) of the city's population within the Braunschweig urban agglomeration area are immigrants or the children of immigrants.