Hanyu City is located in northeastern Saitama Prefecture, with the Tone River flowing to the north. Its terrain is generally flat and it borders Gunma Prefecture. The city is also home to Japan's only wild moss growing area, Hozoji Swamp, a designated national natural monument. The city's name is said to mean "many clays." Blue stripes have been produced here since the late Edo period, and the clothing industry continues to thrive, with indigo dyeing and other products thriving. The precision machinery industry is also thriving. Among the city's cultural assets are the Kanbei Pine, a prefectural natural monument; the remains of Kawamata Barrier, a prefectural historic site; and the Eimyo-ji Tumulus, a prefecturally designated important archaeological site. Tourist attractions include the Saitama Aquarium.