Suminoenotsu is a port which existed in ancient times in Japan.
It is said that this port was constructed by Emperor Nintoku. Suminoenotsu was located in the cove called Sumiyoshi no hosoe, the south of Sumiyoshi Taisha Shrine (Sumiyoshi Ward, Osaka City), which enshrines the sea gods, Sumiyoshi Okami (the great gods of Sumiyoshi).
(Currently, Sumiyoshi no hosoe is Hosoe River (alias), Hosoigawa station)
If you go toward east from Suminoenotsu, you will get to Asuka in Nara Basin.
Before Japanese envoys to Sui and Tong Dynasties China left from Suminoenotsu, they gave a prayer to Sumiyoshi Okami at Sumiyoshi Taisha Shrine, and went toward Kyushu through currently called Seto Inland Sea (it was in the Meiji Period when the idea of Seto Inland Sea came out) via Naniwa no tsu (Naniwa Port).
The fairy tale "Issunboshi" (The Inch-High Samurai) is a story in which Issunboshi sets off from Suminoe no hosoe, gets to the sea of Suminoe (present-day Oosaka bay), and then goes up the Yodo-gawa River toward Kyoto.