Jackson Bay is a gently curving bay 24 kilometres wide, located on the West Coast of New Zealand's South Island. It faces the Tasman Sea to the north, and is backed by the Southern Alps. The westernmost point of the bay is marked by the headland of Jackson Head; in the northeast the end of the bay is less well defined, but the small alluvial fan of the Turnbull and Okuru Rivers might be considered its farthest point. The small Open Bay Islands lie five kilometres off the coast at this point.