A drainage divide, water divide, divide, ridgeline1 or (except in North America) watershed (Brit) is the line that separates neighbouring drainage basins (catchments, or in North America 'a watershed'). In hilly country, the divide lies along topographicalridges (A ridgeline and may be in the form of a single range of hills or mountains; known as a Dividing range). In flat country—especially where the ground is marshy—the divide may be harder to define.
A divide is known by other names:
A watershed is the line between drainage basins. In North America, watershed means the drained land (relative to other rivers or to seas) itself.
A divide in which waters on each side flow to different oceans (for example: the Congo-Nile Divide)
Major drainage divide
Waters on each side of the divide never meet, but do flow into the same ocean (for example: the divide between the Yellow River basin and the Yangtze, or a more subtle example the Schuylkill-Lehigh divide at Pisgah Mountain in Pennsylvania, where two minor creeks divide to flow and grow east and west respectively joining the Lehigh River and Delaware River or the Susquehanna River and Potomac River each tributary complex having separate outlets into the Atlantic.)
Minor drainage divide
Waters part, but eventually rejoin at a river confluence (for example: the Mississippi and Missouri divides)
Drainage divides hinder river navigation. In pre-industrial times, water divides were crossed at portages. Later, canals connected adjoining drainage basins.
^ ab"ridgeline. Dictionary.com" (Dictionary.com Unabridged ed.). Random House Inc. Retrieved 7 September 2013. "ridgeline ridge·line [rij-lahyn] noun 1. a line formed along the highest points of a mountain ridge. 2. an area of higher ground separating two adjacent streams or watersheds."