Trakai Island Castle is an island castle located in Trakai, Lithuania on an island in Lake Galvė. The castle is sometimes referred to as "Little Marienburg". The construction of the stone castle was begun in the 14th century by Kęstutis, and around 1409 major works were completed by his son Vytautas the Great, who died in this castle in 1430. Trakai was one of the main centres of the Grand Duchy of Lithuania and the castle held great strategic importance.
After World War II, a major reconstruction project was begun in 1946; active work started in 1951-1952. The major portion of the reconstruction was finished in 1961. The castle was reconstructed in a 15th-century style.Trakai Island Castle is now a major tourist attraction.