Panama

A dominant feature of Panama’s geography is the mountain range that stretches across the Isthmus of Panama, forming the watershed.

An excerpt from the article 22 facts about Panama

This range, commonly referred to by geographers as the Cordillera Central, is called the Cordillera de Talamanca near the border with Costa Rica, further east it becomes the Sierra de Veraguas.

The Central Cordillera is the conventional line of demarcation between neighboring basins and sub-basins; on one side of the mountains the waters flow into the Pacific Ocean, and on the other into the Atlantic Ocean.