Kransberg Castle is situated on a steep rock near Kransberg (incorporated into Usingen in 1971), a village with about 800 inhabitants in the Taunus mountains in the German state of Hesse. The medieval building, which acquired its current appearance in the late 19th century, served military and intelligence purposes in World War II and during the Cold War. It was returned to its original representation purposes during the second half of the 20th century, and briefly became a business park for small information technology and internet companies in the early post-millennium years.