Kastav (Italian: Castua) is a historical town located about 10 kilometres (6 miles) northwest of Rijeka and about 5 km (3 mi) northeast of Opatija in Primorje-Gorski Kotar County in Croatia.
The total population of Kastav is 10,472 (census 2011).
The census of 2001 had recorded the following settlements:
In the 2011 census, there was only one settlement, Kastav.
Kastav was built on an isolated hill 378 metres (1,240 feet) above sea level. Its historic center, many parks and big forest are attractive to foreign visitors and hikers. The historic walled town contains a church dating from the 13th century which hosts an international music festival each summer.
The Kastav Statute (Croatian: Statut Grada Kastva) was written in 1400, and confirms the status of Croatian city Kastav as an administrative and political centre from the late 14th century.