What is a watershed?
All of the water that empties into that outlet is the watershed. The line where hills or ridges divert water in different directions is the edge of that watershed and is called the divide. Look down at your feet, the depression made in the soil by your footprint is a tiny watershed. Any rain will collect there until it seeps into the soil and flows away. But water that flows overland into your footprint is part of a larger watershed. Look around at the hills, depending on their slope the water is either flowing toward you into your watershed, or if they are high enough will divert the water away from you and into a neighboring watershed. A large watershed is made up of many smaller watersheds because every time water finds an outlet that area becomes a watershed. So all of the water that feeds a tiny creek or stream is a watershed and if that stream flows into a larger stream or river it becomes part of a larger watershed. Watersheds are usually named for the body of water that serves as its outlet.
John Wesley Powell, scientist geographer, put it best when he said that a watershed is: "that area of land, a bounded hydrologic system, within which all living things are inextricably linked by their common water course and where, as humans settled, simple logic demanded that they become part of a community."
The Fox River watershed is part of the larger Fox-Wolf River watershed. The Fox River watershed contains the upper and lower Fox River watersheds as well as many smaller watersheds like the Baird Creek and Apple Creek watersheds.