On the northern side of Broken Bay between Box and Middle Head is a 3.5 km wide south-facing bay that extends 2.5 km north to the entrance to Brisbane Water, with Ocean-Umina beach (NSW 297) extending west of the entrance for 2.5 km (Fig. 4.179 & 4.180). The beach is the southern and seaward end of an 800 ha Holocene barrier system, which has prograded from Woy Woy south to the present beach, a distance of 3 km. The barrier is capped by a series of beach and foredune ridges, all of which are now covered by the houses, apart from the well-vegetated modern foredune, which backs the beach. The beach faces southeast, but is protected by three factors: its location inside Broken Bay, Box Head which extends 2.5 km out into the bay, and the large ebb tide delta of Brisbane Water which maintain shallow shoals extending out 1.5 km to Little Box Head off the eastern Ocean Beach end of the beach. read more

Beach Length: 2.6km