Siegen (ˈziːɡn̩) is a city in Germany, in the south Westphalian part of North Rhine-Westphalia. It is located in the district of Siegen-Wittgenstein in the Arnsberg region. The university town (nearly 20,000 students in the 2018–2019 winter semester) is the district seat, and is ranked as a "higher centre" in the South Westphalian urban agglomeration. In 1975, municipal reforms and amalgamations lifted Siegen's population above the 100,000 mark. The city of Siegen lies in the basin of the upper reaches of the river Sieg. From there, lateral valleys branch off in many directions. The heights of the surrounding mountains, wherever they are not actually settled, are covered in coppice. To the north lies the Sauerland, to the northwest the Rothaargebirge and to the southwest the Westerwald. The nearest cities to Siegen, taking into account average travelling distances, are Hagen to the north , Frankfurt am Main to the southeast , Koblenz to the southwest and Cologne to the west . As the crow flies the distances to these places are, however, (Hagen), (Frankfurt), (Koblenz) and (Cologne). The city lies on the German-Dutch holiday road called the Orange Route, joining towns, cities and regions associated with the House of Orange. The city's total land area is roughly . Its greatest east-west span is about , and its greatest north-south span is about . City limits are long. Siegen lies at a median elevation of above sea level. The city's greatest elevation is the peak of the Pfannenberg at above sea level at southern city limits. Siegen's lowest point is above sea level at Niederschelden at southwestern city limits, which there also forms the state boundary with Rhineland-Palatinate. Roughly 60% of the city's land is wooded, making Siegen one of Germany's greenest cities. The city area is divided into six zones, called Bezirke in German and comparable to boroughs in some cities, which themselves are further divided into various communities (Ortsteile and Stadtteile).