Originally sculpted by glacial melt and retreat, the basins of the twin Hennepin and Hopper lakes were once channels in the Illinois River. As the river meandered and crisscrossed in and around these basins, it created rich waterfowl habitat.

In the 17th century when the first Europeans came across these basins, they were in awe of the numbers of fish and game in the area. The abundance of waterfowl fostered a rich hunting tradition along the Illinois River in the late 1800s and led to the area’s reputation as the “duck capital of the world.”

By 1908, local landowners in the floodplain sought to make the land more amenable to farming by draining it. They formed the Hennepin Drainage and Levee District so they could collectively install levees, ditches, drain tiles, and a drainage pump. The result was a desert of corn and soybeans for most of the 20th century.

The Hennepin and Hopper site in 2000 before restoration began, drained and covered by agricultural fields.

In 2001, the Wetlands Initiative began restoration, first by turning off the pump and disabling the drain tiles. Fed by springs, seeps, and rainfall, the lakebeds refilled within three months, and many native species of plants and animals returned to recolonize the site.

Through 2002 and 2003, restoration work focused on reestablishing native plant communities at the site and stocking the lakes with fish. A portion of the Refuge’s rare seep community was officially designated as an Illinois Nature Preserve.

2004: Audubon designated the site one of Illinois' first Important Bird Areas. The Pied-billed Grebe population exploded, contributing to the state’s decision to "delist" the species from its threatened status.

2005: The project was dedicated as the Sue and Wes Dixon Waterfowl Refuge, in honor of the Dixons' commitment to restoration of the site and in recognition of the huge numbers of migrating waterfowl it supports.

2009 and 2010: TWI and the Illinois Department of Natural Resources faced the challenge of removing the invasive common carp that had degraded the lakes, impacting the Refuge's game fish and waterfowl populations.

The Hennepin and Hopper site after restoration, with lush marsh and lake habitats. 

2011: TWI began an intensive two-year effort to restore rare wet meadow and other habitats at the Refuge by removing invasive woody growth that had encroached more than 120 acres. Friends and supporters commemorated the Dixon Refuge’s 10th anniversary.

2012: The Dixon Waterfowl Refuge was officially designated a Wetland of International Importance under the Ramsar Convention on Wetlands. With a resurgence of the common carp observed in the lakes, TWI undertook a second, more sophisticated effort to eliminate the invasive species.

2014: The multi-year Oak Ridge Trail and Restoration Project began, restoring 70 acres of rare savanna and marsh habitats in the center of the site and establishing a trail leading to it. TWI acquired a new parcel of land, nicknamed Hickory Hollow, expanding the Refuge's total size to more than 3,000 acres.

2015: Intensive restoration of the new Hickory Hollow tract to high-quality upland prairie and savanna habitats began in fall 2015. Construction of the new 2.7-mile Marquis Oak Ridge Trail was completed.