Andros (Greek: Άνδρος) is the northernmost island of the Greek Cyclades archipelago, about 10 km (6 mi) southeast of Euboea, and about 3 km (2 mi) north of Tinos. It is nearly 40 km (25 mi) long, and its greatest breadth is 16 km (10 mi). It is for the most part mountainous, with many fruitful and well-watered valleys.