Althorpe Island, the largest of a group of three islands, and lying beneath the toe of Yorke Peninsula's foot, is 96 hectares in extent and its black and orange cliffs soar 93 metres from the sea. The nearest mainland coast is at Cape Spencer 8 kilometres to the north.

The lighthouse was constructed in 1879, one of several lighthouse built in the late 1870s to light the entrance to Spencer Gulf. The light was illuminated for the first time on 14 February 1879, a revolving white light, with a red sector and a range of 27 miles (43.45 kms). There was only one small beach suitable for landing. Here a small jetty was built for the landing of supplies. From this a ladder was placed for the climb to the top, alongside which ran a small tramline up which supplies could be hauled.

The lighthouse itself was built of limestone and sandstone quarried from the island and stands 64 feet (19.5 metres) high. The glass gallery, lantern and dome were supplied by Chance Brothers. The lantern still remains atop the tower but the light is now supplied by solar power. The Althorpe Island lighthouse was finally demanned in 1991.