The Mopan River is a river in Central America spanning the Petén Department of Guatemala and the Cayo District of Belize. It merges with the Macal River at Branch Mouth, Belize, forming the Belize River, which ultimately discharges to the Caribbean Sea. The drainage area of the combined watershed is 9,434.2 km2 (3,642.6 sq mi). Tributaries of the Mopan include Chiquibul Branch, Ceiba Grande, Salisipuedes, and Delores.