The Numedalslågen River is a significant river located in Norway, flowing through the Numedal valley. It stretches approximately 100 kilometers and is known for its scenic beauty and rich natural surroundings. The river originates from the Hardangervidda mountain plateau and eventually empties into the Larvik Fjord. The river is popular for various recreational activities, including fishing, kayaking, and hiking along its banks. It supports a diverse ecosystem, home to species such as salmon and trout. The Numedalslågen also plays a vital role in local history and culture, with several historic sites and towns situated along its route.