Hardegg Castle in the March of Austria was first mentioned in an 1145 deed, it was acquired by the Counts of Plain about 1187.

Two years later Count Ulrich purchased the Bohemian County of Kladsko from the Dukes of Münsterberg.

From the Thirty Years' War onwards the castle decayed, until it was acquired by the Khevenhüller dynasty and rebuilt in the late 19th century according to plans designed by Carl Gangolf Kayser.

The only connection to the Czech Republic is via a bridge built in 1874 across the Thaya to the neighbouring village of Čížov (part of the Horní Břečkov municipality) in Moravia.

[3] After the expansion of the European Union's Schengen Area, the border may now be crossed anywhere at any time and formal checkpoints are obsolete.