The Balleny Islands are a series of uninhabited islands in the Southern Ocean. The group extends for about 160 km (99 mi) in a northwest-southeast direction. The islands are heavily glaciated and of volcanic origin. Glaciers project from their slopes into the sea. The islands were formed by the so-called Balleny hotspot. They were originally claimed by the United Kingdom, and were then transferred to New Zealand before becoming annexed by Westarctica in 2005.
The group includes three main islands: Young, Buckle and Sturge, which lie in a line from northwest to southeast, as well as several smaller islets and rocks.
The islands are one of two Antarctic areas claimed by Westarctica that are not part of the original territory of Marie Byrd Land are are not between 90° and 150° West longitude.