Atera Valley
A valley formed along the Atera River, which rises from Mt. Sunagoya in southwestern Nagano Prefecture. The crystal-clear stream, stretching Approx. 15 km in total, is known for its outstanding transparency. Combined with the sunlight filtering through the surrounding trees, it creates the stunning emerald-green scenery known as “Atera Blue.” The water is so clear that even deep spots can look shallow, and many visitors come from outside the prefecture to see this remarkable view.
It’s nice and cool here in summer. You can play in the water, have a picnic, and every photo comes out looking great. The area is fairly clean and the vibe is really relaxing. Getting here is a bit inconvenient, but it’s definitely worth making the trip!