Margaret River is a limestone reef platform a quarter-mile across and extending almost a half-mile to sea, flanked by deepwater bays on either side, and facing more or less due west into the Indian Ocean.
A half-mile south is another narrower reef shelf known as the Bombie, which pulls southwest swells into a heavy bowling right; a mile north and a half-mile offshore is a short, shallow right reef called The Box, heavily photographed in recent years, thanks to its quick, intense, highly photogenic barrels.
Tucked inside the bay between the River reef and The Box is a beachbreak zone with an occasionally good right rip bowl, partly created by the thin outflow of Margaret River itself, a small stream snaking down through the surrounding bushland. The River reef is predominantly a left, peaking a long way offshore and peeling in a series of heavy, thick sections down to a final bumpy finish into the shallows inside the reef line.
It handles anything from 5 to 18 feet. It's a complex wave with many moods, sometimes mushy and fading into deep water on south-angled swells, sometimes wedging and forming gnarly dangerous barrels on swells from the west.
Good rights will occasionally grind off the peak, especially on smaller days when the takeoff moves closer in on the massive, broad reef.