The location of Gummi, a city mentioned on the Piazzale delle Corporazioni in Ostia, is disputed. Statio 17 mentions Gummi: navicvlari Gvmmitani, with a depiction of a grain measure. The name has nothing to do with gum. Two ancient bishoprics named Gummi are known. One is Gummi in Africa Proconsularis, today Bordj-Cédria, Tunisia. Bishops are known from 411, 525 and 1053 AD. The other is Gummi in Africa Byzacena, today Henchir-El-Senem or Henchir-Gelama, Tunisia. Bishops are known from 484 and 641 AD. Bordj-Cédria is a suburb of Tunis (ancient Carthage) on the coast of the Gulf of Tunis. Henchir-El-Senem is in south-east Tunisia, ca. 16 km inland.
Gummi is linked by some with Alipota (the location of which is unknown, according to some Mahdia) and Salakta (which is Syllectum). The basis for this is not clear. For the time being everything points to a harbour near Carthage. On the Piazzale in Ostia the office of the shippers from Carthage (statio 18) is adjacent to that of of Gummi, with which it shows similarities.