[3] It has an estimated mass of (7±2)×1013 solar masses,[4] making it the second richest galaxy cluster within 100 million light-years, after the considerably larger Virgo Cluster.

It lies primarily in the constellation Fornax, with its southern boundaries partially crossing into the constellation of Eridanus, and covers an area of sky about 6° across or about 28 sq degrees.

It also shows the gravitational effects of a merger of a galaxy subgroup with the main galaxy group,[6] which in turn lends clues about the associated galactic superstructure.

[3] Fornax can be divided into two subclusters: the main cluster, centered on NGC 1399, and a subgroup 3 degrees to the southwest centered on the lenticular galaxy NGC 1316 that is currently in the process of infalling with the largest subcluster to merge with it, and whose galaxies are experiencing relatively strong star formation activity.

[5] As with many other galaxy clusters, Fornax intracluster medium is filled with a hot, rarefied gas that emits X-rays.