Samegai-juku has a very long history, and was mentioned by name in the Nihon Shoki, which was completed in 720 AD, and in the even earlier Kojiki chronicle in connection with the Yamato Takeru mythology.

It was located on the ancient Tōsandō highway connecting the capital of Heian-kyō with the provinces of eastern Japan, and continued to be mentioned in the diaries and the poems of travelers in the Heian and Kamakura periods.

One of the main attractions of this station was the fresh and clear waters from the nearby Jizogawa river and many travelers thought of Samegai as a proper resting place.

Per the 1843 "中山道宿村大概帳" (Nakasendō Shukuson Taigaichō) guidebook issued by the Inspector of Highways (道中奉行, Dōchu-būgyō), the town had a population of 539 people in 138 houses, including one honjin, one waki-honjin, and 11 hatago.

These buildings are the famous Rokken jaya of Samegai-juku, six hatago built for the purposes of housing the retinues which accompanied daimyō processions (while the lord himself stayed at the honjin).