It consists of mostly granitic islands and reefs that provide breeding sites for Australian sea lions and support colonies of short-tailed shearwater.

Of the roughly 30 islands and reefs in the archipelago, those lying furthest from the coast of the Eyre Peninsula are the Isles of St Francis, after the largest.

[2] The archipelago was named in 1802 by Matthew Flinders after Dutch diplomat Pieter Nuyts, who was the senior official of the Dutch East India Company on the ship 't Gulden Zeepaert ("The Golden Seahorse"), captained by François Thijssen who mapped 1800km of the southern coastline of Australia from Albany to Ceduna in the course of a 1626–27 voyage from the Netherlands to Formosa and Japan.

It is covered by a mix of grassland, saltbush and low shrubland and supports a large population of muttonbirds (estimated at 273,000 pairs).

[4] Masillon Island is located about 2.5 kilometres (1.6 miles) south of St Francis, it was named in 1802 in the course of Baudin’s expedition after a Bishop of Clermont, Jean Baptiste Massillon.

[6] Fenelon Island is located about 1.5 kilometres (0.93 miles) south of Masillon, it was named by Baudin after François Fénelon, a French archbishop and theologian.

[4] It features heathland on shallow soils and supports a large population of white-faced storm petrels (13,000 pairs),[6] as well as a sea lion breeding colony.

[4] Egg Island is located about 400 metres (1,300 feet) north-east of St Francis, it is dome shaped with a high point 41 m above sea level.

[6] Dog Island is located about 300 metres (980 feet)east-north-east of St Francis, it has saltbush shrubland and muttonbirds (1816 pairs).

[4] The island first obtained protected area status as a fauna conservation reserve declared under the Crown Lands Act 1929-1966 on 16 March 1967 .

Since sheep grazing ceased the vegetation has become dominated by regenerating native plant communities with patches of mallee woodland.

[4] The island first obtained protected area status as a fauna conservation reserve declared under the Crown Lands Act 1929-1966 on 16 March 1967 .

[4] Lilliput and Blefescu Islands are small islets which were only officially named in 2007, lying off East and West Franklin respectively, they both support sea lion breeding colonies.

An isolated subspecies of the southern brown bandicoot (Isoodon obesulus nauticus) is endemic to the archipelago and confined to St Francis and the Franklin Islands.