Boeotia, sometimes alternatively Latinised as Beotia (/biːˈoʊʃiə/ or /biːˈoʊʃə/; Greek: Βοιωτία, Modern Greek: [vi.oˈti.a], Ancient Greek: [bojɔːtía]; modern transliteration Voiotía, also Viotía, formerly Cadmeis), is one of the regional units of Greece. It is part of the region of Central Greece. It was also a region of ancient Greece. Its capital is Livadeia, and its largest city is Thebes.
Boeotia lies to the north of the eastern part of the Gulf of Corinth. It also has a short coastline on the Gulf of Euboea. It bordered on Megaris (now West Attica) in the south, Attica in the southeast, Euboea in the northeast, Opuntian Locris (now part of Phthiotis) in the north and Phocis in the west.
The main mountain ranges of Boeotia are Mount Parnassus in the west, Mount Helicon in the southwest, Cithaeron in the south and Parnitha in the east. Its longest river, the Cephissus, flows in the central part, where most of the low-lying areas of Boeotia are found.
Lake Copais was a large lake in the center of Boeotia. It was drained in the 19th century. Lake Yliki is a large lake near Thebes.