Casteltermini is a comune (municipality) in the Province of Agrigento in the Italian region Sicily, located about 70 kilometres (43 mi) southeast of Palermo and about 25 kilometres (16 mi) north of Agrigento.

Casteltermini borders the following municipalities: Acquaviva Platani, Aragona, Cammarata, Campofranco, San Biagio Platani, Sant'Angelo Muxaro, Santo Stefano Quisquina, Sutera.

Casteltermini was founded in 1629 by the local noble Gian Vincenzo Maria Termini e Ferreri, hence the name.

Casteltermini is noted for its extensive mines of rock salt and sulphur.

Historical population

Year Pop. ±% 1861 7,549 —     1871 8,194 +8.5% 1881 9,275 +13.2% 1901 13,022 +40.4% 1911 15,092 +15.9% 1921 17,116 +13.4% 1931 11,786 −31.1% 1936 12,256 +4.0%	Year Pop. ±% 1951 13,766 +12.3% 1961 12,464 −9.5% 1971 10,555 −15.3% 1981 10,380 −1.7% 1991 10,132 −2.4% 2001 8,782 −13.3% 2011 8,422 −4.1% 2021 7,384 −12.3%
Source: ISTAT

• Chiesa Madre - "Mother Church"
• Church of San Giuseppe
• Hermitage of Santa Croce
• Church of Madonna del Carmelo
• Church of Jesus and Mary
• Antiquarium
• Ethnographic Museum
• Memorial of World War I and II Veterans, located in the city center in front of the Chiesa Madre. The names on the upper half represent the veterans of World War I. The names listed on the lower half represent the names of veterans from WW2.

• Châtelet, Belgium

• Niccolò Cacciatore (1770-1841), astronomer
• Michele Caltagirone (1854-1928), sculptor

• Official website