On April 10, 1955, Hachiya merged with the villages of Kakuda, Yamada, Mikekado, Kurotsuchi, Senzoku, Yokobu, Aikawa, and Iwaya to form the city of Ujima.

Buzen has a mayor-council form of government with a directly elected mayor and a unicameral city council of 13 members.

In terms of national politics, the city is part of the Fukuoka 11th district of the lower house of the Diet of Japan.

An industrial zone has been formed around Ujima Port, with Daihatsu Auto Body moving into neighboring Nakatsu City, automobile-related factories have also been built in Buzen.

The Buzen Chikujo Medical Association Nursing Advanced Vocational School is also located in the city.