The economy of Caltanissetta remained heavily reliant on agriculture until the 19th century, when a heavy sulfur mining industry began. Soon 275 sulfur mines were created in the Nissena province, employing 32,000 workers. A renowned firm established in the city is the Fratelli Averna SpA, producing a liqueur sold in the whole of Italy and beyond, the Amaro Averna.
The city has long been stricken by poverty, especially the west side
