 The city limits were expanded from 1951 to 1955 by annexing neighboring Suzumenomiya town and Hiraishi, Yokokawa, Mizuhono, Kunimoto, Shiroyama, Tomiya, Toyosato, and Sugatagawa villages and the part of Shinoi village from Kawachi District and Kiyohara village from Haga District.In 1996, Utsunomiya was designated a core city within increased autonomy.On March 31, 2007, Utsunomiya absorbed the towns of Kamikawachi and Kawachi (both from Kawachi District), pushing the population of Utsunomiya City over 500,000.