There are a few legends that have been passed down through the generations that describe the secret behind how the name “Nagareyama,” which means “flowing mountain,” came to be. The most popular legend is that long ago, a part of Akagi Mountain (a mountain located in the neighboring Gunma Prefecture) broke off, and the debris flowed down the Edo River to where present day Nagareyama is. Since Japanese culture has always been deeply intertwined with nature and the environment, it is theorized that the city was named after this significant natural event. The shrine is called Akagi Shrine in honor of these roots connected to Akagi Mountain, and is often described as the origin of the city of Nagareyama.

One of the most prominent sights in Nagareyama can be found at Akagi Shrine. It is a massive Shimenawa that is hung on the torii gates of the shine. A Shimenawa is a rope that is commonly hung in Shinto shrines as a ward against evil spirits. Every year around October is when things get lively at Akagi Shrine, as people from around the region gather to help weave a new rope. The end result is a massive shimenawa that is over 6.5 meters long, weighing in around 500kg.

A week after the new rope is adorned on the Torii Gate, is the annual Akagi Shrine Festival. The area is decorated with bright lanterns, and during the main event, the Omikoshi parade, a portable shrine is carried around the Honcho area. In a shocking grand finale, the omikoshi is rushed up the steep steps of Akagi Shrine. Visitors of the festival are welcomed with traditional Japanese taiko music, and are able to snack on the yakisoba and candied apples from the various food booths.