Today only an irrigation channel remains in the approximate location of the original river path.

The village of Hanyū was created within Kitasaitama District, Saitama with the establishment of the modern municipalities system on April 1, 1889.

On September 1, 1954 Hanyū merged with the neighboring villages of Shingō, Sukage, Iwase, Kawamata, Iizumi, and Tegobayashi and was elevated to city status.

Hanyū has a mayor-council form of government with a directly elected mayor and a unicameral city council of 14 members.

In terms of national politics, the city is part of Saitama 12th district of the lower house of the Diet of Japan.