Aarhus, or Århus, is the second-largest city in Denmark. The principal port of Denmark, it is situated on the east side of the peninsula of Jutland in the geographical center of Denmark. Aarhus is the seat of the council of Aarhus municipality with 307,119 inhabitants and 242,914 (1 January 2010) in the inner urban area, and about 800,000 inhabitants within 1/2 hour transport (StorÅrhus). The city claims the unofficial title "Capital of Jutland". Aarhus is the main and biggest city in the East Jutland metropolitan area (Danish: Byregion Østjylland). which is a co-operation in the eastern Jutland with 17 Municipalities. With more than 1.2 million people living in the area it represents approximately 23% of the population of Denmark and is the second largest metropolitan area after the Copenhagen metropolitan area.
During the Middle Ages the city was called Arus, and in Icelandic chronicles, it was known as Áróss. It is a compound of the two words ār, genitive of ā ("river", Modern Danish å) and ōss ("mouth", obsolete in Modern Danish; in Modern Icelandic this word is still used for "river delta"). The city is located on the mouth of the small river, Århus Å (Å being the Danish word for a small river). Through regular sound development, Medieval Danish Arus became Aars or Oes, a form which persisted in the dialects of the surrounding parishes until the 20th century. In 1406, Aarhus became prevalent in the written sources, and gradually became the norm in the 17th century. Aarhus is probably a remodelling after the numerous Low German place names in -husen, possibly as a result of the influence of German merchants. The city was mentioned for the first time by Adam of Bremen who stated that "Reginbrand, bishop of the church of Aarhus (Harusa)" participated in a church meeting in the city of Ingelham in Germany.
The city lies roughly at the geographical centre of Denmark on the peninsula of Jutland. Forests reach from the south into the city to within a kilometre (0.6 mi) of the city centre, because the city has grown around the forest, and some forest areas are completely surrounded by the city, such as Riis Skov. The city is built mostly around the harbour, which is predominantly industrial, although a large recreational marina is situated south of it as an extension.
While some of the highest points in Denmark are close to the city, the general landscape is typically hilly, interspersed with forests and meadows; the city itself is very hilly north of the centre (by Danish standards, that is; see Highest hill, Denmark). The coastline consists mainly of sandy beaches, but stony areas are not uncommon. The immediate coastal regions are not heavily populated due to a national policy of keeping residences inland rather than crowding the coast. The city lies at the junction of railway lines from all parts of the country. To the south west (about 21 km (13 mi), by rail) lies a picturesque region that contains the Gudenå. Several larger lakes extend West from the Skanderborg railway junction and rise to heights exceeding 152 metres (499 ft) at Himmelbjerget. The railway traverses this district of moorland and woodland to Silkeborg.