Gießen is a city in the federal state (Bundesland) of Hesse in Germany, capital of the Gießen district. There are as of 2003 approx. 72.909 inhabitants.

The history of the city goes back to 775, when the first to-be suburbs "Wieseck" and "Unsenheim" where fist mentioned. Gießen itself was founded by Graf Wilhelm von Gleiberg as a waterside-castle. In 1607 the University of Gießen founded to be a counterpart to the Lutheran University in the City of Marburg.

Wilhelm Liebknecht, founder of the Social Democratic Party of Germany, was born on 29 March 1826 in Gießen.

Heavy bombing destroyed about 75% of Gießen in 1944, most of the city's historic buildings were destroyed.

In 1977 Gießen was merged with the neighboring city Wetzlar to form the new city Lahn, however this attempt to reorganize the administration was very unpopular and was reverted in 1979.