Ultar Sar (also Ultar, Ultar II, Bojohagur Duanasir II) is the southeasternmost major peak of the Batura Muztagh, a subrange of the Karakoram range. It lies about 10 km (6.2 mi) northeast of the Karimabad, a town on the Karakoram Highway in the Hunza Valley, part of the Gilgit District of Gilgit–Baltistan, Pakistan. While not one of the highest peaks of the Karakoram, Ultar Sar is notable for its dramatic rise above local terrain. Its south flank rises over 5,300 metres (17,388 feet) above the Hunza River near Karimabad, in only about 10 km (6.2 mi) of horizontal distance. Combined with its strategic position at the end of the Batura Muztagh, with the Hunza River bending around it, this makes Ultar a visually striking peak.
Ultar Sar also gained fame in the 1990s as supposedly the world’s highest unclimbed independent peak. This was incorrect, as Gangkhar Puensum in Bhutan is higher, and remains unclimbed (and off-limits) as of 2007 (two other higher peaks are also reputedly unclimbed and of independent stature). However, that perception did add to the appeal of the peak, and a number of expeditions attempted to climb it.