Debris ejected from the impact that created Pharos may have formed Hippocamp, a small moon whose orbit is unusually close to Proteus's.

[4] Pharos was first discovered in the Voyager 2 spacecraft's flyby of Neptune and its system of moons on 25 August 1989, being one of the first identifiable features on Proteus.

[5][6]: 1447  The discovery of Proteus (then provisionally designated S/1989 N 1[7]) itself was announced roughly two months prior on 7 July 1989 as Voyager 2 approached the Neptune system.

[8] The impact basin was provisionally named in a 1992 paper by Steven K. Croft after the island of Pharos, whose only surviving remnant is the Ras el-Tin promontory in modern-day Alexandria, Egypt.

The floor of Pharos appears to be domed, but nevertheless lacks a clear central peak that characterizes central-peak impact craters.

A series of depressions further surround Pharos, with a system of north-south oriented valleys bordering the southeast rim being the most prominent.

[2]: 407, 412, 417 [3]: 48–49, 51 The Pharos impact would have also excavated large amounts of debris and ejecta, much of which would have escaped into direct Neptune orbit.

The fragments would impact at velocities of roughly 7.5 km/s (17,000 mph) relative to Triton, enough to excavate craters 7 kilometres (4.3 miles) in diameter.