Bochum (, BOHKH-uum; US: -⁠əm; German:[ˈboːxʊm]; Westphalian: Baukem) is a city in North Rhine-Westphalia. With a population of 372,348 (April 2023), it is the sixth-largest city (after Cologne, Düsseldorf, Dortmund, Essen and Duisburg) in North Rhine-Westphalia, the most populous German federal state, and the 16th-largest city in Germany. On the Ruhr Heights (Ruhrhöhen) hill chain, between the rivers Ruhr to the south and Emscher to the north (tributaries of the Rhine), it is the second largest city of Westphalia after Dortmund, and the fourth largest city of the Ruhr after Dortmund, Essen and Duisburg. It lies at the centre of the Ruhr, Germany's largest urban area, in the Rhine-Ruhr Metropolitan Region, the second biggest metropolitan region by GDP in the European Union, and belongs to the region of Arnsberg. There are nine institutions of higher education in the city, most notably the Ruhr University Bochum (Ruhr-Universität Bochum), one of the ten largest universities in Germany, and the Bochum University of Applied Sciences (Hochschule Bochum).