The Upper Lakes are a system of 12 lakes: Prošćansko, Ciginovac, Okrugljak, Batinovac, Veliko, Malo, Vir, Galovac, Milino, Gradinsko, Veliki Burget and Kozjak separated by travertine barriers. The lakes lie on an impervious belt consisting of Upper Triassic dolomite. Prošćansko and the Kozjak lakes are the largest lakes in the whole system.
The Matica River flows into the Prošćansko lake and the river itself is formed by a confluence of the Black and White Rivers in the Plitvički Ljeskovac village. The lake is the second largest in the overall Upper Lakes system, with a depth of 37 m. The left shore is located in the Highest Protection Zone, therefore, access to visitors is forbidden. The Labudovac plane and the Labudovačka barrier border the lake at its far end.
Lakes Ciginovac and Okrugljak follow. On the north-west, the waters from Ciginovac flows into Okrugljak. There is a beautiful Labudovac Fall that is over 20 m high, draping the now dried up part of the Labudovac travertine barrier, below which there is a multitude of cracks, half-caves and caves called jointly: the Cave Garden. In the past, passage was possible under this part of the barrier, using steps carved out in the rock. Beneath the Labudovac fall itself used to be an entrance into the 50-m long Janeček's cave. Today, a part of the fall tumbles onto the very opening and entry is no longer possible.
The lakes that come next are Batinovac, the Great Lake (Veliko jezero), the Small Lake (Malo jezero), Vir and Galovac. Alongside the north edge of Galovac beneath the Stubica plateau we find marvellous specimens of dolomitic rock. The eastern part of the lake, characterised by a chain of abundant waterfalls called Prštavci (the Sparkling Falls) is followed by Milino, Gradinsko and Burgeti lakes.
Near the edge of Burgeti, in the woods, hide the remains of a small stone building, a part of a past endeavour to create a hydro power plant. The water from Burgeti flows into Lake Kozjak.
Lake Kozjak is the last of the Upper Lakes and is situated at an altitude of 534 m. Its deepest point is 46 m. Apart from waters from the Burgeti waterfall, the steady Rječica brook flows into Kozjak. The eastern part of Kozjak is built of karstified rudist limestone of Cretaceous age.
About 400 years ago, Lake Kozjak consisted of two lakes separated by a fall about 40 m high. However, the travertine barrier near today's Kozjak barrier (the Kozjak bridges) began to grow at a greater pace than the one that separated the two lakes. The lake’s water level gradually covered the fall and when the barrier was sunken, the two lakes merged into the lake we see today. A peculiarity of this lake is Štefanija's island, 275 m long and 60 m wide, with an area of 0,014 sq.km. The island is formed of Triassic dolomite. Beech and hazel-trees grow here, along with the other low shrub.