From the Wikipedia page [1]
Lahn-Dill is a Kreis (district) in the west of Hesse, Germany. Neighboring districts are Siegen-Wittgenstein, Marburg-Biedenkopf, Gießen, Wetteraukreis, Hochtaunuskreis, Limburg-Weilburg, Westerwaldkreis.
n 1977 the district Gießen was merged with the districts Wetzlar and Dillkreis to the new Lahn-Dill-Kreis. However this big district wasn't popular, so in 1979 Gießen was split from it.