Propadený zámek, Hillfort ruins near Branov, Czech Republic.

Propadený zámek is a hillfort on a promontory of the Křivoklátská vrchovina at about 340 m above sea level, roughly 1 km southwest of Branov. Four rampart lines divide the surface into five parts. The first stone rampart, about 40 cm high, crosses the narrowest point; 40 m northeast is a massive second rampart, partly damaged by quarrying, whose stone base and burnt daub with wood impressions indicate a burnt rampart. The third rampart lies 150 m further; the fourth, best visible in the terrain, dates to the Middle Hillfort period. The only documented entrance was a passage about 3 m wide between the fourth rampart and the cliff edge.

The hillfort was first mentioned by Jan Erazim Vocel. Josef Ladislav Píč labelled it Slavic without evidence, while Josef Maličký placed its fortification in the La Tène period. Surface survey by Tomáš Durdík found no settlement traces and suggested it served as a refuge. Excavations in 2006–2007 confirmed use in the Middle and Late Hillfort period, and also in the Hallstatt or Late Bronze Age.

The name Propadený zámek, also recorded as Na Zpropadeném zámku, was first published by Jan Erazim Vocel. Archaeologists have debated the site's builders: Josef Ladislav Píč called it Slavic without evidence, Josef Maličký placed it in the La Tène period, and Tomáš Durdík found no traces of settlement and suggested it served as a refuge for people of the surrounding countryside in times of danger.

The site lies about one hour on foot from the V Luhu ferry crossing, following an unmarked trail along the river. Sturdy footwear and some endurance are important since the path climbs toward the hilltop.

The name "Propadený zámek" ("Fallen-through Castle") was first recorded by Jan Erazim Vocel; the site is also called "Na Zpropadeném zámku". Archaeologist Tomáš Durdík found no evidence of settlement and suggested the ramparts served as a refuge for people from the surrounding countryside in times of danger.