The Chagres River, in central Panama, is the largest river in the Panama Canal's watershed. The river is dammed twice, and the resulting reservoirs—Gatun Lake and Lake Alajuela—form an integral part of the canal and its water system. Although the river's natural course runs northwest to its mouth at the Caribbean Sea, its waters also flow, via the canal's locks, into the Gulf of Panama to the south. The Chagres thus has the unusual claim of drainage into two oceans.