[1] It includes the Nine Islands (Kepulauan Sembilan) in the Gulf of Bone off the east coast of the southern peninsula of Sulawesi; this archipelago forms an administrative district within the regency.

The regency's principal town lies at Sinjai, a port situated on the east coast of that peninsula.

The small group of mountainous, forest-covered islands known as the Sembilan Islands lies on the east coast of South Sulawesi province and is northeast of the port town of Sinjai.

Notwithstanding the name, ten named islands are forming the group, as Pulau Kanalosatu and Pulau Kanalodua are structurally linked and normally classed as one island (Kanalo).

[1] The table also includes the locations of the district administrative centers, the number of administrative villages in each district (totaling 67 rural desa and 13 urban kelurahan), and their postcode (s).