Čiovo (Italian: Bua) is a small island located off the Adriatic coast in Croatia with an area of 28.8 km2 (length 15.3 km, width up to 3.5 km), population of 6,071 inhabitants (2001) and its highest peak is 218 m (Rudine).
The centre of the island has geographical coordinates 43°30′N 16°17′E / 43.5°N 16.283°E / 43.5; 16.283, and the annual rainfall is about 900 mm.
Čiovo is located in central Dalmatia, protecting the citiy of Trogir and Kaštela gulf. On its SE part it is only two km distant from the cape Marjan, on northern part it is connected to the mainland with a small bascule bridge in the old centre of Trogir, and actually Trogir spread itself on the island. Besides the part of Trogir, on the island there are several villages: Arbanija, Žedno, Okrug Gornji, Okrug Donji, Slatine and Prizidnica.
The vegetation is typically Mediterranean, consisting mainly in understory (holm oak, myrtle, wormwood, juniper etc.). On the northern side (exposed to the wind bura are forests of pine and cypress. Major crops include olives, figs, almonds, vines and citrus fruit.
In the Middle Ages, Čiovo had many villages and it was a place for lepers. Remainings of the pre-Romanesque church of St. Peter have been found near Slatine, in the Supetar cove. The medieval church of St. Maurice (Sv. Mavro) has been preserved in Žedno and the pre-Romanesque church of Our Lady near the Sea (Gospa pokraj mora). The population of Čiovo increased in the 15th century through the settlement of refugees who fled from the Turks. Simultaneously, the suburban areas of Trogir also extended to Čiovo.
The church and the Dominican monastery of the Holy Cross (Sv. Križ) (5 km from Trogir) were built in the 15th century by the masters Ivan Drakanović and Nikola Mladinov. In the Franciscan monastery of St. Anthony (Sv. Antun) There are a painting of Palma the Younger and a sculpture of St. Magdalene by Ivan Duknović. Along the coast is the church of St. Jerome. On the eastern coast, up the cliff is the nicely located hermitage church of Our Lady of Prizidnica. Along the south-western side of Čiovo, vis-a-vis the beach, is a small island called Fumija, with the remains of the late antique or early mediaeval church of St. Fumija and farm buildings of the Benedictine monks from Trogir.