Torre della Tonnara dell'Ursa, Coastal watchtower in Cinisi, Italy

Torre della Tonnara dell'Ursa is a pale, flat-roofed complex on a low rocky peninsula at Fondo Orsa, in the territory of Cinisi. A long single-storey block with a small arched doorway adjoins a two-storey section with small square windows, beside which rises the square tower, its walls streaked dark near the base. The tower was built in 1569 by order of the Abbey of San Martino and later served the adjoining tuna fishery.

Built in 1569 by order of the Abbey of San Martino, the tower was recorded as a fortified baglio with two or three dammusi. In 1578 the royal architect Tiburzio Spannocchi found it complete and urged continuous guard, a call repeated by Camillo Camilliani in 1584, when the Deputazione del Regno di Sicilia took over its military management. In 1860 it passed to the military domain and in 1867 was listed among towers to be decommissioned.

The name may derive from the Arabic "ìrsa", meaning anchorage, fitting the shallow bay beside the tower; a link to "marsah", port, is also proposed. The tonnara was leased in 1491 to the Palermitan Mattheo de la Chimia for 10 onze, and in 1714 a felucca loaded cheese and farm produce at the small harbour it guarded.

The tower stands at Fondo Orsa on a low rocky peninsula in Cinisi, reached by a service road just past the Marina di Cinisi motorway exit. A pedestrian underpass beneath the motorway leads to the tower but is often flooded in winter. The complex belongs to the Comune di Cinisi, which granted some rooms to the local Legambiente section, contactable for a guided visit.

In 1804 the tower was manned by two torrari, paid 17 onze a year and equipped with three cannons and two muskets. Around 1863 four cannons could still be seen; one bore the inscription "Magister Ioannes de Balo me fecit 1576", another the motto "A vice tronitrui tui formidabunt 1618" beneath an image of Saint Benedict.