The Kajaaninjoki River is a river located in Finland, flowing through the town of Kajaani. It is approximately 100 kilometers long and serves as a tributary to the Oulujoki River. The river is known for its scenic beauty and is a popular spot for outdoor activities such as fishing and canoeing. The river's course is characterized by a mix of calm stretches and rapids, making it an attractive destination for nature enthusiasts. The Kajaaninjoki River also plays a significant role in the local ecosystem, supporting various species of fish and wildlife in the surrounding areas.