Willowbrook is a village in DuPage County, Illinois, United States, in the Chicagoland area.

Originally an unincorporated area of nearby Darien, Willowbrook grew from the Ridgemoor subdivision.

It was incorporated as a village in 1960[3] Construction of U.S. Route 66 along Willowbrook's south edge led to the development of several new gas stations and restaurants.

It is bordered by the suburban villages of Hinsdale, Westmont, Clarendon Hills, Burr Ridge, and Darien, along with unincorporated areas of DuPage County.

In September 2018, the Illinois Department of Public Health began a cancer incidence study based on the recommendation of the Agency for Toxic Substances and Disease Registry.

[13] A local facility, Sterigenics International, Inc., uses a 'probable carcinogen' called Ethylene Oxide to sterilize medical equipment.

According to the EPA fact sheet, 'Long-term exposure to ethylene oxide can irritate the eyes, skin, nose, throat, and lungs, and harm the brain and nervous system (causing effects such as headaches, memory loss, numbness).

[14] On September 30, 2019, Sterigenics announced the closing of the Willowbrook facility eliminating key source of cancer causing chemical.