The Chikuma River is the longest river in Nagano Prefecture, Japan, stretching approximately 367 kilometers. It flows through the picturesque landscapes of the Japanese Alps and is known for its clear waters and scenic beauty. The river is an important water source for agriculture and supports various ecosystems along its banks. The Chikuma River is also significant for recreational activities, including fishing, kayaking, and river rafting. It is home to several species of fish, making it a popular spot for anglers. The river's surroundings feature beautiful parks and walking trails, attracting both locals and tourists alike.