The Iwaki River is a river that crosses western Aomori Prefecture, Japan. It is 102 kilometers (63 mi) in length and has a drainage area of 2,544 square kilometers (982 sq mi). Under the Rivers Act of 1964 the Iwaki is designated as a Class 1 River and is managed by the Japanese Ministry of Land, Infrastructure, Transport and Tourism. The Iwaki River is the longest river in Aomori Prefecture, and is the source of irrigation for the large-scale rice and apple production of the prefecture. The Iwaki River, in the Tōhoku region north of the Fukushima Daiichi Nuclear Power Plant, remains unpolluted by radioactive materials after the Fukushima Daiichi nuclear disaster. Testing for caesium-134 and caesium-137 is carried out and published on a bimonthly basis.

Aomori Prefecture ([a̠o̞mo̞ɾʲikẽ̞ɴ]) is a prefecture of Japan in the Tōhoku region. The prefecture's capital, largest city, and namesake is the city of Aomori. Aomori is the northernmost prefecture on Japan's main island, Honshu, and is bordered by the Pacific Ocean to the east, Iwate Prefecture to the southeast, Akita Prefecture to the southwest, the Sea of Japan to the west, and Hokkaido across the Tsugaru Strait to the north. Aomori Prefecture is the 8th-largest prefecture, with an area of 9,645.64 km2 (3,724.20 sq mi), and the 31st-most populous prefecture, with more than 1.18 million people. Approximately 45 percent of Aomori Prefecture's residents live in its two core cities, Aomori and Hachinohe, which lie on coastal plains. The majority of the prefecture is covered in forested mountain ranges, with population centers occupying valleys and plains. Aomori is the third-most populous prefecture in the Tōhoku region, after Miyagi Prefecture and Fukushima Prefecture. Mount Iwaki, an active stratovolcano, is the prefecture's highest point, at almost 1,624.7 m (5,330 ft).