Kusatsu Onsen is a famous hot spring resort located in the mountains of Nagano Prefecture, Japan. Known for its high-quality sulfuric waters, it has been a popular destination for relaxation and healing for centuries. The town features numerous public baths, ryokan (traditional inns), and a unique outdoor bath called Yubatake, which means "hot water field." Visitors to Kusatsu can enjoy various activities, including hiking in the surrounding mountains and exploring the scenic beauty of the area. The onsen's therapeutic properties are believed to help with various ailments, making it a sought-after spot for wellness and rejuvenation.