Lake Oulujärvi is a large lake located in northern Finland, covering an area of approximately 340 square kilometers. It is situated in the region of Kainuu and is known for its scenic beauty, surrounded by forests and small islands. The lake is a popular destination for outdoor activities such as fishing, boating, and hiking. The lake has a maximum depth of about 50 meters and is fed by several rivers, including the Oulujoki River. It is also home to diverse wildlife, making it an important ecological area. Lake Oulujärvi freezes over in winter, offering opportunities for ice fishing and winter sports.