Medieval castle ruin Nünegg, Castle ruin and archaeological site in Lieli, Switzerland.

Nünegg is a ruined hilltop castle above the village of Lieli in the municipality of Hohenrain, Canton Lucerne. Its characteristic nine-cornered ground plan gives it the name «Nünegg». A steel corset secures the tower, and a spiral staircase installed in 2016 leads to a viewing platform at a height of 10 metres, reached by 50 steps.

The castle was built in 1283 by the lords of Lieli. After their line died out it changed hands several times until it burned in 1386 during the turmoil of the Sempach War. Around 1700 the ruin passed into the possession of the Canton of Lucerne.

Locals call the ruin "Nünegg" after its nine-cornered ground plan, and it appears on the list of Swiss cultural properties of national significance. The tower platform, reached by 50 steps, looks over the village of Lieli and Lake Baldegg.

The ruin is reached via marked hiking trails through the municipality of Hohenrain in the Canton of Lucerne. It is accessible from the outside without requiring special equipment or preparations.

The ruin's nine-cornered ground plan earned it the nickname "Nünegg" (nine corners). In 2011 the collapsing tower was braced with a steel corset, and a spiral staircase was installed inside it in 2016, giving access to the viewing platform 10 metres up.