La Pasión River flows through the western half of Petén. There are a number of Mayan archeological sites near its shores that can be visited via boat. La Pasión River is often used for transportation during the rainy season, when the water is much higher than other times of the year.
The drainage system of La Pasión River and its tributaries cover an area of 1,930 mi2 (5,000 km2), making it a major watershed in this region. Tributaries that begin in Alta Verapaz feed into the river, which eventually joins with the Salinas River to form the Usumacinta River and drain into the Gulf of Mexico.
For travelers, the river’s main significance is the archeological sites that lie near its banks. La Pasión River was once a major trade route for the Maya and helped establish a number of important cities throughout the river basin, including Cancuén and Ceibal, the latter of which was a major ceremonial center. Many trips run along La Pasión River via the town of Sayaxché, including excursions to both Ceibal and Dos Pilas.
The river is also very biologically diverse—it harbors 45 species of endemic fish and has nearly 300 species of endemic birds living near its borders. 150 medicinal plants can be found in the forests that grow alongside the river.