According to the Institut Géographique National from 1 January 2007 until July 2013 the geographic centre of the European Union was located on a wheat field outside of Gelnhausen.

The bars in the right are taken from the coat of arms of the Lords of Hutten, who owned the area around Bad Soden and Salmünster, formerly part of the defunct Schlüchtern district.

In 1986 the district parliament decided to start a developing project with the Diriamba region in Nicaragua.

Also in 1990 first contacts with the Russian Rayon Istra were started, which resulted in an official partnership in 1992.

In 2000 a treaty of friendship was signed with the Italian province Belluno, as well as a partnership with the Israeli city Ramat Gan.