The Numata River Terraces are one of the most remarkable geological landscapes in Numata City, Gunma Prefecture. This extensive terrace landscape developed near the confluence of the Katashina River and the Tone River.
Because the terraces are exceptionally clear in form and impressive in scale, they are sometimes described as “the most beautiful river terraces in Japan.” The landscape has also been featured extensively in geography textbooks and educational materials, making Numata’s river terraces familiar to many people in Japan from their school days.
The Numata River Terraces developed slightly upstream from where the Katashina River joins the Tone River. The terraces have deep, clearly defined steps that can be recognized even from a considerable distance.
The landscape has such a pronounced three-dimensional structure that its character as a river terrace is immediately apparent.
One of the most distinctive features is that the urban center of Numata is built on the highest terrace surface. The city center spreads across this elevated terrace, creating a height difference of approximately 70 meters from JR Numata Station, the city’s main railway gateway.
This difference in elevation becomes especially apparent when exploring the city in person, allowing visitors to experience the dramatic scale of Numata’s terrain.
The Numata River Terraces extend beyond the city center into surrounding areas. Beautiful terrace formations can also be seen near the confluence of the Akaya River and Tone River in Tsukiyono, Minakami Town, along the Usune River, and between Ogoe and Kainose in Showa Village.
These landscapes are also highly regarded and are considered among the most impressive river terrace landscapes in Japan.
From areas around Numata Park and Kamikawada, visitors can look toward the foothills of Mount Mitsumine and see the terraces spreading along the river valleys in a pattern reminiscent of rice terraces.
The scale of the terrain can also be clearly appreciated from around the Katashina River Bridge on the Kan-Etsu Expressway. The height of the bridge supports is almost level with the elevation of the upper terrace, providing a striking visual indication of the enormous scale of the landscape.
The Numata Basin is believed to have once been a lake in the distant past. Rivers flowing down from the surrounding mountains carried mud and sand into the basin, gradually filling the lake over a very long period of time.
The lake eventually became a broad plain. As the courses of the rivers changed, continued erosion gradually carved the land into the distinctive staircase-like terrain seen today.
On both sides of the rivers, the terraces form a series of steps that resemble giant rice paddies, creating a magnificent landscape shaped entirely by natural forces.
The Numata River Terraces are therefore the result of sedimentation and erosion working over immense spans of geological time.
The Numata River Terraces can be viewed beautifully from numerous locations around the city. Particularly recommended viewpoints include elevated areas such as Shiisaka Pass, Mount Amagoi, and Mount Koshigawa, where the overall form of the terraces can be seen more clearly.
Other popular viewpoints include Shinjuku-no-Mori Forest, areas along the Bokyo Line, the open-air baths at Shirasawa Kogen Onsen “Bokyo-no-Yu”, and restaurants along National Route 120.
These locations offer the opportunity to admire the magnificent terrain while enjoying a meal or relaxing in a hot spring, creating a particularly memorable way to experience Numata’s landscape.
In the past, plans were considered to construct dams using the river terraces and basin landscape around Numata. However, the plans were not realized following strong opposition and concern from local residents, and the beautiful landscape has remained preserved.
The river terraces are much more than a geological feature. They have long been closely connected with the history and daily lives of the people who live in the region.
The terrain has influenced the development of the castle town built on elevated ground, transportation routes along the foot of the terrace cliffs, and the use of the surrounding land for agriculture. In this way, Numata’s distinctive geography has played an important role in shaping the city itself.
From the Numata Interchange on the Kan-Etsu Expressway, visitors can reach the various viewpoints via National Route 120 or the Bokyo Line.
From JR Numata Station, buses take approximately 20 to 40 minutes, depending on the destination. Choose the appropriate local bus route according to the viewpoint or sightseeing area you wish to visit.
The Numata River Terraces are a landscape that is best appreciated not only through textbooks but also by seeing the terrain in person.
The enormous terraces, which preserve the geological history of the land, display different expressions throughout the seasons and continue to fascinate visitors.
As you explore the area, take a moment to consider the immense natural processes that shaped the landscape over countless years, and experience the grandeur of the Numata River Terraces for yourself.