It borders on the municipalities of Canicattì, Delia, Enna, Marianopoli, Mazzarino, Mussomeli, Naro, Petralia Sottana, Pietraperzia, San Cataldo, Santa Caterina Villarmosa, Serradifalco and Sommatino.

The city lies between three hills (Sant'Anna, Monte San Giuliano, and Poggio Sant'Elia),[6] which form a basin which comprise part of the historical centre and South.

This is an area of barren hills, with a colour ranging from white to dark grey, where mud volcanoes of around one meter in height rest on volcanic sediment.

On 20 August 2008 a State of Emergency was declared because of events involving the Santa Barbara district in Caltanissetta in the preceding days.

During the morning of August 11, 2008, geological instability caused the opening of rifts in the ground surface, varying from ten centimetres to a metre in diameter.

[citation needed] After the Second Punic War, Castra Nicia came under Roman rule, but as in the rest of Sicily, the influence of the invaders remained superficial.

The Carthaginian name, similar to the Arabic word نساء nisā’ (meaning 'women') resulted in the Saracen name قلعة النساء Qal‘at al-Nisā’ ('Fort of the Women'),[8] since Italianized to Caltanissetta.

In 1407, King Martin I ceded the territory of Caltanissetta to Matteo Moncada II, of the noble Spanish House of Montcada,[5][11] which already owned the estate of Paternò, and subsequently the area fell into great decay.

In 1812, the Moncada seignory ended after a rule of 406 years, when the feudal constitution was abolished and Caltanissetta was turned into the 22nd Comarca of Sicily.

After many Nisseni had taken part in his Thousands deeds, Giuseppe Garibaldi entered the city, together with Cesare Abba and Alexandre Dumas.

Three years later the King Umberto I visited Caltanissetta along with his wife Margherita of Savoy and his son Victor Emmanuel III.

During the Second World War, as part of the Allied landing in Sicily (in July 1943), Caltanissetta suffered several bombings during which 351 civilians were killed.

Caltanissetta's economy remained heavily reliant on agriculture until the 19th century, when sulfur mining industry began extensively.

Its main element is an omnidirectional antenna of 286 meters high, which holds the record for the tallest structure in Italy, it stands on the Sant'Anna hill of 660 m s.l.m.

[15] In the 2021/2022 football championship, the two main teams are: The city also hosts "Città di Caltanissetta" Tennis Tournament, part of the ATP Challenger Tour.