Erythrum was a city and bishopric in Roman Africa, which remains a Catholic titular see.

The city, identified with modern Uaili-Et-Trun,[1] was important enough in the Roman province of (Creta and) Cyrenaica and later the split-off province Libya Superior or Libya Pentapolitana to become a suffragan of its capital's Metropolitan of Cyrene.

Ultimately, it was annexed by the Turkish Ottoman Empire in 1517 when it was part of the Tripolitania Vilayet.

The Diocese of Erythron was a center of Early Christianity in the Pentapolis of North Africa.

The seat of the Diocese was the Roman town of Erython, tentatively identified with the village of Uaili-Et-Trun in today's Libya.