Divide, a ridge of land so situated that water on one side flows in one direction, while water on the other side drains in the opposite direction. Most divides consist of highly elevated land, such as hills or mountain ranges. For example, the Rocky Mountains form a divide that runs north and south. This ridge, called the Continental Divide, separates waters that flow eastward into the Mississippi River and Gulf of Mexico from those that drain westward into the Pacific Ocean.
Some divides are lower lying than hills or mountains. A height of land, running east and west across generally low sections of the United States and Canada, separates the rivers flowing northward into the Gulf of St. Lawrence, Hudson Bay, and the Arctic Ocean from waters draining southwestward into the Mississippi River.
