Komarnik Lake with Agata’s and Frank’s Trail

The Komarnik Reservoir lies about 2 km west of Lenart in the Slovenske Gorice Hills. It is one of five reservoirs in the Pesnica Valley and covers 26 hectares, with an average depth of 1.5 metres. Its history dates back to the 16th century, when the noble Herberstein family—owners of the nearby Hrastovec Castle—developed it for fish farming. In the 1960s, the lake was redesigned as a retention reservoir to hold back high waters, yet it retained its natural appearance and became an important hotspot of biodiversity.

A natural refuge

After the regulation of the Pesnica River and extensive land reclamation in the Pesnica Valley, Komarnik and its surroundings became the last refuge for many rare and endangered plant and animal species. The lake is especially rich in waterbirds—it is considered one of Slovenia’s most important nesting sites for water birds, and it is also frequently used as a stopover by migratory birds.

The wider area around Komarnik also includes fishponds and streams, and even the otter, which indicates a well-preserved aquatic environment. Particularly remarkable is the fact that the lake is home to 35 species of dragonflies, including endangered species such as loška zverca, zgodnji trsničar, and nosna jezerka—with the largest population of the latter found here in Europe, while elsewhere they have already disappeared completely.

Frank’s and Agata’s Trail

A relaxing walking path has been arranged around Lake Komarnik, equipped with information boards and two birdwatching hides, allowing visitors to observe birds in their natural habitat.

One of the trails is Frank’s Trail, about 2.5 km long, which leads visitors through flowering meadows where chamomile fills the air in summer. Along the way, interpretive panels introduce the natural features and values of the area.

The second, equally scenic route is Agata’s Trail, linking Hrastovec Castle, Lake Komarnik, and the Black Cross monument. The trail is dedicated to the tragic love story of Agata and the manor lord Friderik Herberstein, offering not only a nature experience but also a cultural and historical one. Beautiful views of Hrastovec Castle open up along the way, adding an extra highlight to the walk.