Městské opevnění v Kadani, Medieval fortification system in Kadaň, Czech Republic.

The fortification of Kadaň's Old Town forms an irregular rectangle about 500 metres north-south and 350 metres east-west, with three wall circuits on most sides but only two along the Ohře River, where they stand directly on granite rock. Four main gates—Žatecká, Vodní, Svatá and Prunéřovská—plus the smaller Katova branka pierced the walls, and the barbican of the Žatecká Gate survives.

Construction of the fortifications started in the second half of the 13th century under King Přemysl Otakar II, establishing Kadaň as one of Bohemia's strongest defensive centers. The walls continued to be reinforced over subsequent centuries and remained strategically important through the early modern period.

Each year around Epiphany on 6 January, the Kadaň dean blessed the gates and walls with holy water and incense, and the walls were closed at about ten in the evening. In 1570 a man who climbed the walls at night and mocked the guard was chained to the pillory and expelled from the town for ten years.

The 2019 reconstruction of two of the five wall sections added a fountain, benches, a wooden pergola, cobblestone paving and a new drainage system. The work followed a 2016 study by architect Petr Uhlík and cost 15.4 million korunas.

The walls were treated as almost sacred: each year around Epiphany the Kadaň dean blessed the gates and walls with holy water and incense. Guards manned the gates by a 1579 town order, with three men on the Ohře bridge and three at the Žatecká Gate.