Cottbus (German pronunciation: [ˈkɔtbʊs] ) or Chóśebuz (Lower Sorbian pronunciation: [ˈxɨɕɛbus]) is a university city and the second-largest city in the German state of Brandenburg after the state capital, Potsdam. With around 100,000 inhabitants, Cottbus is the most populous city in Lusatia. Cottbus lies in the Sorbian settlement area (Serbski sedleński rum) of Lower Lusatia, and is the second-largest city on the River Spree after Berlin, which is situated around 125 km (78 mi) downstream. The city is located on the shores of Germany's largest artificial lake, the Cottbuser Ostsee (Chóśebuski pódzajtšny jazor).
Cottbus is the political and cultural center of the Lower Sorbian-speaking Sorbs, also known as the Wends in Lower Lusatia; the overall center of Sorbian culture is Bautzen/Budyšin. Cottbus is the largest bilingual city in Germany. Signage is mostly in German and Lower Sorbian. The city hosts several Lower Sorbian institutions like the Lower Sorbian version of the Sorbischer Rundfunk/Serbski rozgłos, the Lower Sorbian Gymnasium, and the Wendish Museum. The use of the Lower Sorbian language, however, is more widespread in the surrounding municipalities than in the city itself. The Wendish Quarter is a part of the city supposed to resemble the traditional Sorbian architectural style.