The West Branch of the DuPage River, 35.0 miles (56.3 km) long,[2] starts at Campanelli Park in Schaumburg[4] within Cook County and continues southward through the entire county of DuPage, including the towns of Bartlett, Wayne, Wheaton, Warrenville, Winfield and Naperville (including through its riverwalk), as well as McDowell Grove.

St. Joseph Creek, a tributary of the river's East Branch, runs through the small town of Belmont.

The two branches meet at the southern end of Knoch Knolls Park, between Naperville and Bolingbrook.

The combined DuPage River continues southward from that point, through Plainfield & Shorewood and then west of Joliet.

Like many local bodies of water, both branches of the DuPage River seriously overflowed after the "Flood of 1996", when approximately 17 inches (430 mm) of rain fell on the area within a 24-hour period, on July 17–18 of that year.