Hrádek u Třebonína, Medieval hillfort in Lomec, Czech Republic

Hrádek u Třebonína, also called the Lomec hillfort, is a medieval fortified site of uncertain purpose and age on a rocky spur above the left bank of the Medenický potok, about 500 m west of Třebonín. Its most accessible northern side is guarded by a 76 m long outer ditch up to 8 m wide and 3 m deep, a rampart rising 5 m above the ditch floor, a narrow platform, a second ditch about 5 m wide and a second rampart about 2 m wide.

No written sources mention the site. Kliment Čermák first described it in 1883. A small excavation in the 1970s by Zdeněk Smetánka and Jiří Škabrada yielded no finds that could date the fortification. Based on settlement patterns, archaeologists assume it was built around the mid-12th century as a refuge during the internal colonization of Bohemia.

The name Lomec is used for the hillfort, though the site lies in the cadastral area of Lomec u Úmonína, about 500 metres west of Třebonín. No written sources mention the site; the first description was published by Kliment Čermák in 1883. The place is also called Hradiště Lomec.

Access to the rocky spur runs from the east through a steep gully about ten metres wide; the rest of the eastern side and the whole southern side are bounded by sheer rock walls, and lower rock formations block the west. The most open side, the north, is where the multiple ramparts stand, so the outer ditch, 76 metres long, 8 metres wide and up to 3 metres deep, is met first.

The northern side features a particularly intricate defense system with three successive embankments, the first rising approximately 5 meters (16 feet) above an 8-meter (26 feet) wide moat. This layered approach to protection shows how medieval builders thought strategically about slowing attackers.