Nelson Island (Qaluyaaq in Central Yup'ik) is an island in the Bethel Census Area of southwestern Alaska. It is 42 miles (68 km) long and 20–35 miles (32–56 km) wide. With an area of 843 square miles (2,183 km²), it is the 15th largest island in the United States. It is separated from the Alaska mainland to its north by the Ningaluk River, to its east by the Kolavinarak River and from Nunivak Island to its southwest by the Etolin Strait.