最上川
The first historical record of what is now Akita Prefecture dates to 658, when Abe no Hirafu conquered the native Ezo tribes at what are now the cities of Akita and Noshiro. Abe, then governor of Koshi Province (the northwestern part of Honshū bordering the Sea of Japan), established a fort on the Mogami River, and thus began the Japanese settlement of the region.