Demographics of Cologne and on 1 April 1888 ended in a first major incorporation. The territorial expansion, beginning in the late 19th century, were significant marks for the city's population growth. Major communal reorganizations took place in 1910, 1914, 1922 and 1975. Demographics of Cologne Cologne () is Germany's fourth-largest city and the largest city in the Rhineland. As of 31 December 2011, there were officially 1,017,155 residents. The city is center of the Cologne/Bonn Region with around 3 million inhabitants (including the neighboring cities of Bonn, Hürth, Leverkusen, and Bergisch Gladbach). The walls of Colonia Agrippina covered an area of 96.8 hectares,
Districts of Cologne while maintaining close economic links to the city of Cologne. More than half of the estates here were in the hands of citizens of Cologne or the same becoming residents in these areas. Since 1886, the Cologne City Council intensified negotiations with the surrounding communities, and on 1 April 1888 ended in a first major incorporation. Since then the city has expanded with major reorganizations in 1910, 1914, 1922 and 1975. Districts of Cologne Since the last administrative reform in 1975, the City of Cologne is made up of nine Stadtbezirke and 86 Stadtteile. "Stadtbezirk" literally translates as city district,