The Luján River is a significant waterway located in the province of Buenos Aires, Argentina. It flows approximately 120 kilometers (75 miles) and is a tributary of the Rio de la Plata. The river is known for its scenic beauty and plays a vital role in the local ecosystem, supporting various wildlife and plant species. The river's basin is home to several towns, including Luján, which is famous for its historical architecture and the Basilica of Our Lady of Luján. The Luján River is also important for agriculture and recreation, providing water for irrigation and opportunities for fishing and boating activities.