The state reserve encompasses a significant portion of the northeastern coast of the island, stretching from Lake Martha Lavinia and Penny's Lagoon in the north to the Sea Elephant River estuary in the south.

In 1978, land consisting of the Lavinia Nature Reserve and the Sea Elephant Wildlife Sanctuary was listed in the now-defunct Register of the National Estate.

[6] The name derives from the 52-ton schooner Martha Lavinia, wrecked on a reef offshore in 1871 near what is the site of the state reserve while carrying a cargo of potatoes from Tasmania to Adelaide, which gave its name to several features along the north-eastern King Island coast.

[4] The state reserve provides habitat for many birds and other animals, including the critically endangered orange-bellied parrot, the extremely rare King Island subspecies of the brown thornbill, and the Southern Hairy Red Snail.

Short-tailed shearwaters have colonies in the dunes behind Lavinia Beach while fairy terns nest on the sand spit at the mouth of the Sea Elephant River.