[citation needed] The largest river in Giessen is the Lahn, which divides the town in two parts (west and east), roughly 50 kilometres (31 miles) north of Frankfurt am Main.

Giessen came into being as a moated castle in 1152 built by Count Wilhelm von Gleiberg,[4] although the history of the community in the northeast and in today's suburb called "Wieseck" dates back to 775.

During the Second World War, a subcamp of the Buchenwald concentration camp was in the Heil- und Pflegeanstalt Licher Straße.

[5][6][7] Heavy bombing destroyed about 75 percent of Giessen in 1944, including most of the town's historic buildings.

[8] The base is a converted German Army Air Field which is reflected in some of the buildings including the housing area.

[13] Manisch is a dialect of rotwelsch spoken in and around Giessen by people in lower income neighbourhoods, some of which are known as "Eulenkopf", "Gummiinsel", "Heyerweg" and "Margaretenhütte".

Climate in this area has mild differences between highs and lows, and there is adequate rainfall year-round.