List of state leaders in 257

Africa

*Kush - Tegerideamani II, King of Kush (246-266?)

Asia

*Bactria and Gandhara - Peroz I, Kushanshah (c.250-265)
*Baekje - Goi, King of Baekje (234-286)
*Chera -
*#Ilamcheral Irumporai, King of Chera (241-257)
*#Perumkadungo, King of Chera (257-287)
*Gaya - Geodeung, King of Gaya (199-259)
*Goguryeo - Jungcheon, King of Goguryeo (248-270)
*Gupta Empire - Maharaja Sri-Gupta, King of the Gupta Empire (240-280)
*Iberia - Mithridates II Mihrdat, King of Iberia (249-265)
*Kushan Empire - Kanishka III, King of the Kushans (255-275)
*Persia - Shapur I of Persia, King of Persia (241-272)
**Armenia - Artavazde VI, King of Armenia (252-283)
*Shu Han - Liu Shan, Emperor of Shu Han (223-263)
*Silla - Cheomhae, King of Silla (247-261)
*Tuoba - Tuoba Liwei, Chieftain of the Tuoba clan (219-277)
*Wei - Cao Mao, Emperor of Wei (254-260)
*Western Kshatrapas - Rudrasen II (256-278)
*Wu - Sun Liang, Emperor of Wu (252-258)

Europa

*Roman Empire -
**Valerian, Roman Emperor in the East (253-260)
**Gallienus, Roman Emperor in the West (253-268)