Twofold Bay

Twofold Bay
Looking from Eden across Twofold Bay to wood chip supplies.
Twofold Bay Location of Twofold Bay in New South Wales
Location	South Coast, New South Wales
Coordinates	37°03′55″S 149°54′04″E / 37.06528°S 149.90111°E / -37.06528; 149.90111Coordinates: 37°03′55″S 149°54′04″E / 37.06528°S 149.90111°E / -37.06528; 149.90111
Type	An open oceanic embayment
Primary inflows	Towamba River, Nullica River
Primary outflows	Tasman Sea, South Pacific Ocean
Catchment area	11 km2 (4.2 sq mi)
Basin countries	Australia
Surface area	30.7 km2 (11.9 sq mi)
Average depth	10.9 m (36 ft)
Water volume	334,559 megalitres (11,814.8×10^6 cu ft)
Frozen	never
Settlements	Eden
Website	NSW Environment & Heritage

Twofold Bay is an open oceanic embayment that is located in the South Coast region of New South Wales, Australia.

The bay was named by George Bass, for its shape of two bights. The northern bight is called Calle Calle Bay; while the southern bight is known as Nullica Bay.

The bay is also known for the "Killers of Eden", the killer whales which helped a group of whalers in their search for other whales. The best-known of these was Old Tom whose skeleton is preserved in Eden's local museum.

Located near the town of Eden, Twofold Bay is approximately 100 kilometres (62 mi) to the north of the border between Victoria and New South Wales. The bay is fed from the Nullica River and Towamba River that both flow into Nullica Bay.

The catchment area of the bay is 11 square kilometres (4.2 sq mi) with a volume of 334,559 megalitres (11,814.8×10^⁶ cu ft) over a surface area of 30.7 square kilometres (11.9 sq mi), at an average depth of 10.9 metres (36 ft); making the bay reputedly the third deepest natural harbour in the Southern Hemisphere.

Close to North Head is a conspicuous islet, Mewstone Rock. About 5 kilometres (3.1 mi) south of the islet is Red Point which forms the southern headland of the bay. Eden and the Port of Eden are located in the bay. The historical town of Boydtown is located to the west of the bay, located on Boydtown Beach which stretches south from the mouth of the Nullica River.

Local waters including Twofold Bay is recognized as one of twelve coastal aggregation areas for Southern Right Whales in Australia.