Tsumago-juku was the forty-second of the sixty-nine post towns on the Nakasendō. It is located in Nagiso, Kiso District, Nagano Prefecture, Japan. It has been restored to its appearance as an Edo-era post town and is now a popular tourist destination.

The Nakasendō , also called the Kisokaidō (木曾街道), was one of the five routes of the Edo period, and one of the two that connected Edo to Kyoto in Japan. There were 69 stations (staging-posts) between Edo and Kyoto, crossing through Musashi, Kōzuke, Shinano, Mino and Ōmi provinces. In addition to Tokyo and Kyoto, the Nakasendō runs through the modern-day prefectures of Saitama, Gunma, Nagano, Gifu and Shiga, with a total distance of about 534 km (332 mi).