Ōi-juku was the forty-sixth of the sixty-nine stations of the Nakasendō connecting Edo with Kyoto in Edo period Japan. It is located in former Mino Province in what is now part of the city of Ena, Gifu Prefecture, Japan. From Ōi-juku to the next post town, Ōkute-juku, there are 13 hills to pass over.