A Watershed is: all the land area that drains to a specific body of surface water such as a stream, river, lake or ocean.

The Lower Olentangy Watershed: encompasses approximately 150 square miles of land that drain into the Lower Olentangy River. This 32-mile section of the Olentangy River begins at the Delaware Dam in Delaware County and runs south until it ends at the confluence with the Scioto River in the city of Columbus, Franklin County. The State Scenic Olentangy River extends for 22 miles from the Delaware Dam south to Wilson Bridge Road was so designated in 1973 because of its exceptional water quality. For further information on Ohio's state scenic rivers visit ODNR Scenic Rivers.

The Olentangy River Watershed is part of the larger Scioto River Basin, which drains south to the Ohio River and is therefore, part of the larger Ohio River Watershed and subsequent Mississippi River Watershed.

Other sources of information about watersheds:

• The Lower Olentangy Watershed Inventory: Chapter 2 – Watershed Physiography (PDF: 1.24 MB)
• Ohio Department of Natural Resources: Ohio Watersheds and Drainage Basins Maps
• Natural Resource and Conservation Service: Ohio 14-digit Subwatersheds
• The Nature Conservancy: Map of Watersheds of Ohio

At the time of the last census, the Lower Olentangy Watershed was home to approximately 250,000 people living in Franklin and Delaware counties. The watershed includes the city of Delaware, Ohio Wesleyan University, and significant portions of Delaware County, the fastest growing county in the state of Ohio; as well as Ohio State University and a significant northern portion of Columbus, a growing city and Ohio’s state capital.