Lake Pääjärvi is a freshwater lake located in the region of Finland. It is known for its clear waters and scenic surroundings, making it a popular spot for outdoor activities such as fishing and hiking. The lake is part of the Kymijoki river basin and contributes to the local ecosystem. The area around Lake Pääjärvi is rich in biodiversity, hosting various species of fish and birds. It is also surrounded by forests, providing a habitat for wildlife. The lake's tranquil environment attracts visitors seeking relaxation and nature experiences throughout the year.