Bielefeld is a city in the Ostwestfalen-Lippe Region in the north-east of North Rhine-Westphalia, Germany. With a population of 341,730, it is also the most populous city in the administrative region of Detmold and the 18th largest city in Germany.
The historical centre of the city is situated north of the Teutoburg Forest line of hills, but modern Bielefeld also incorporates boroughs on the opposite side and on the hills. The city is situated on the Hermannsweg, a hiking trail which runs for 156 km along the length of the Teutoburg Forest.
Bielefeld is home to a significant number of internationally operating companies, including Dr. Oetker, Gildemeister and Schüco.
It has a university and several technical colleges. Bielefeld is also famous for the Bethel Institution, and for the Bielefeld conspiracy, which satirises conspiracy theories by claiming that Bielefeld does not exist. This concept has been used in the town's marketing and alluded to by Chancellor Angela Merkel.