The fortress Gradina is located in Drnis, at an elevation of 344 m above sea level, above the canyon of the river Cikola. Built on the site of strategic importance, offers a breathtaking view of the city and mountain Promina, spreads at Peter's field and back into the deep rocky canyon Cikola. It is assumed that it was part of the system of fortresses of the noble family Nelipic. During the rule of the Ottoman Empire Gradina was rebuilt for defensive purposes.

With the arrival of the Venetians, in the late 17th century, its demolition was ordered. However, It was restored soon because of the threat of Turkish breaking in, which was present until 1715. god. In the 19th century fortress has lost all function and become a source of building materials for the growing city Drnis. Today remains visible on the southern side are part of the medieval fortress, while the central tower and the north-eastern defense wall are from the period of Ottoman rule. Gradina is registered as a historical monument.

The fortress of Bogočin

The ruins of the medieval fortress of Bogočin are visible on the left bank of the Krka River, on a high rock near the village of Bogatić.

It was likely erected by the Croatian noble family Nelipić, while later it was ruled over by the great Martinušić family.

A single, excellently preserved medieval road lead to Bogočin, and the fortress could only be entered via a drawbridge. In the early 16th century, it was taken over by the Turks and remained under the Turkish administration until 1684.

The fortress of Ključica

Ključica is the largest and best preserved medieval fortress in Krka National Park. It was erected by the Croatian noble family Nelipić in the 13th century over the canyon of the Čikola River in order to protect their estate from their rivals, the noble family Šubić.

Due to its strategic position, Ključica was often a source of conflict for its masters, the people of Šibenik. In 1546, it was conquered by the Turks who ruled here until 1648 when they were finally forced out. Afterwards, Ključica has been abandoned and no one ever lived here again.

Od tada je Ključica napuštena i više se nikada u njoj nije živjelo.

The fortress of Kamičak

The ruins of the medieval fortress of Kamičak stand between Roški slap and Visovac Lake. According to historical records from 1345, the Croato-Hungarian king Ludovic confirmed the heritage right of Ivan Nelipić over Kamičak.

The later Turkish invasions and their occupation of the entire area meant the loss of the significance of Kamičak, and it was abandoned. Kamičak is also colloquially referred to Utješinovića Grad, as the first Croatian Cardinal Juraj Utješinović was born here in 1482.

Marko Mišljenović, appointed Croatian Ban by the Croato-Hungarian King Ladislav in 1506, was born here as well.

The fortress of Šubićevac

Šubićevac fortress is located south-east of St. John's fortress and a couple of meters lower than St. John's fortress.

It was constructed in the same year as St. John's fortress, in 1646 and it contributed very much to the defence of the Town of Šibenik from the Turkish attacks in 1647. For a long time it was named the fortress of the baron Degenfeld, after the Venetian soldier of the German origin that lead the defence of the town from the Turks.