Buka Island lays at the northern end of Bougainville Island geographically these islands of the north Solomon's province makes up part of the Solomon Island chain. Buka lies 5° south of the equator. The island is 70 kilometres long and 17 kilometres wide with a land area of 611 kilometres2. Buka Island consists of mainly uplifted coral on the east coast and the Parkinson range in the west is volcanic in origin and rises to a height of 485 metres. The hills around this area are heavily forested. The island receives on average 2400 millimetres rainfall per year with the rain being localised.
Buka Township is located at the southern end of the island. The town has a variety of shops selling foods and other goods, the market located in the centre of town has plentiful green vegetables and fruit and a large area dedicated to selling Buai (edible nut chewed for stimulation).
The town lies on the northern side of Buka passage which separates it from Bougainville mainland and the town of Kokopau, the water flowing through the passage reaches speeds of 12 knots.