I
River and outlet of Lake Nicaragua , southern Nicaragua.
It flows from the lake's southeastern end, forms the border of Nicaragua and Costa Rica, and empties into the Caribbean Sea; it is 124 mi (199 km) long. Near its mouth it divides and forms the Juanillo Menor, Colorado, and San Juan rivers.
II
River, southwestern U.S. It rises in the San Juan Mountains of southern Colorado, on the western side of the Continental Divide .
It flows southwest into New Mexico, northeast into Utah, and west to the Colorado River . It is 360 mi (580 km) long and not navigable. The section of the river where the boundaries of New Mexico, Utah, Arizona, and Colorado meet, into which the San Juan has carved numerous S-shaped canyons more than 1,000 ft (300 m) deep, is known as the Goosenecks.