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.The municipality, which includes the island Andros and several small, uninhabited islands, has an area of 380.041 km2 (146.735 sq mi).

The largest towns are Andros (town), Gavrio, Batsi, and Ormos Korthiou. The island is famous for its Sariza spring at Apoikia, where the water flows from a sculpted stone lion’s head. Palaeopolis, the ancient capital, was built into a steep hillside, and the breakwater of its harbor can still be seen underwater. Andros also offers great hiking options.