The Yaak River is a tributary of the Kootenai River located in northwestern Montana, USA. It flows through the Yaak Valley, an area known for its scenic beauty and diverse wildlife. The river is approximately 30 miles long and is popular for recreational activities such as fishing, kayaking, and hiking along its banks. The Yaak River is part of the larger Kootenai River watershed, which eventually flows into Lake Koocanusa. The surrounding region is characterized by dense forests and mountainous terrain, making it a habitat for various species, including elk and bald eagles. The river plays a vital role in the local ecosystem and economy.