Lastovo (Italian: Lagosta, Latin: Augusta Insula, Greek: Ladestanos, Illyrian: Ladest) is an island, town and municipality in the Dubrovnik-Neretva county in Croatia. The island has an area of 46 km² and a population of 835 of which 93% are ethnic Croats.
The municipality is slightly bigger because it includes another 45 islands and islets covering a total area of approximately 56 km².
The island is rich in architecture, featuring many buildings from the 15th and 16th centuries. There are a large number of churches for its relative size, which is a testament to the island's long standing Roman Catholic tradition. The major cultural event, apart from the normal celebrations on the Catholic calendar, is the event known as the Poklad, or carnival. The island today relies mostly on its natural beauty and preservation to attract a reasonable amount of tourists each season. Currently the Croatian government is preparing a bill to make the island and its archipelago a nature park.
Lastovo, like the rest of Roman Dalmatia, was settled by Illyrians. The Romans conquered and settled the entire area until the Avar invasions and Slavic migrations in the 7th century. The Croat tribes secured most of the Dalmatian seaboard. Around the year 1000 the Venetians attacked the island destroying the settlement due to the islands participation in piracy along the Adriatic. In the 13th century, Lastovo joined the Dubrovnik Republic where it mostly enjoyed a certain level of autonomy until the republics conquest by the French under Napoleon. Austria then ruled the island for the next two centuries until it finally became a part of  Croatia.