The province extends to the central part of Sicily in the northwestern direction where the capital is located. The commune of Resuttano is found in an enclave of the province of Palermo near Caltanissetta between Monte Stretto and Portella del Vento. Another example in the same province is that of the two small localities of Cannetti and Corfidato, two frazioni of the comune of Enna, 15 km (9.3 mi) away, within the territory of the comune of Caltanissetta.
The land extends to the Gela Plain and into the Gulf of Gela.
As of June 30, 2005, the main communes by population are: