Yonezawa Domain
Okitami County was an ancient place name in part of Dewa Province. Under the Tokugawa shogunate, the portion which became Nishiokitami district consisted of 116 villages entirely within the area controlled by Yonezawa Domain. The area was designated Yonezawa Prefecture in August 1871, renamed Okitami Prefecture in December 1871, and became part of Yamagata Prefecture in 1876. Nishiokitami District was created on November 1, 1878. With the establishment of the municipalities system on April 1, 1889, it was organized into one town (Nagai) and 16 villages.