Jiljov, Rock castle in Holany, Czech Republic.

Jiljov is the ruin of a small Romantic summer palace, or letohrádek, built in the first half of the 19th century east of Holany. Its oval core, a landscaped sandstone rock, is ringed by a moat 15 to 32 metres wide; excavation in 1970 uncovered clay-bonded sandstone masonry, a retaining wall, at the edge of the island.

Long called a fortress and linked by August Sedláček to a manor house, the site was shown by a 1970 archaeological survey to have been shaped only in the 19th century. Vincenc Karel Kounic, owner of Zahrádky Castle after 1820, had the relief and rock modified as part of the park around it. It has been a protected cultural monument since 1965.

Jiljov is a Romantic ruin, not a medieval castle: August Sedláček linked the site to a manor house, but 1970 archaeological research showed the terrain modifications date only to the 19th century. Vincenc Karel Kounic, owner of Zahrádky Castle after 1820, initiated them as part of the surrounding landscape design.

Access is via a short detour from the yellow-marked hiking trail between Holany and Zahrádky, about one kilometre east of Holany. The site has an oval plan ringed by a 15–32 m wide moat, so expect uneven ground and a damp ditch edge rather than a marked summit path.

The site is often called a fortress, but the 1970 archaeological dig found the terrain had been reshaped only in the 19th century, after 1820, on the initiative of Vincenc Karel Kounic, owner of Zahrádky Castle. The masonry uncovered at the edge of the island is sandstone joined with clay, a retaining wall rather than a medieval keep.