river rising in northeastern Guatemala as the Río Mopán and flows about 180 mi (290 km) northeast past Benque Viejo, San Ignacio (El Cayo), and Roaring Creek (site of Belmopan, capital of Belize 【formerly British Honduras】) into the Caribbean Sea at Belize City. During the pre-Columbian era, it served as one of the main trade arteries of the Maya Indians. It is navigable for small craft with enclosed propellers from Belize City as far as the Guatemalan border and is used to carry lumber for export and chicle to market areas.