Naganuma (長沼) is at the westernmost part of Ninomiya, Tochigi Prefecture. The area is largely rural - rice and strawberry farming is the largest industry. The Kinugawa River marks the boundary of Naganuma (and so too, Ninomiya, Tochigi and Haga District, Tochigi).
References
Naganuma, Tochigi Wikipedia(Text) CC BY-SA