The broad, bluff-lined river basin was rich in fish, shellfish, waterfowl, and peltry, exploited by Native Americans and by 1800s pioneers.
[3] The Hennepin area was so rich in wetland productivity that the New York City-based American Fur Company operated a fur-trading post here in the 1810s.
In 2000 eight farm families agreed to sell most of the Hennepin drainage district to a young not-for-profit conservation organization, The Wetlands Initiative.
[3] In December 2014, The Wetlands Initiative purchased 417 acres of adjacent upland, the Hickory Hollow parcel adjoining Illinois Route 26.
[6] The parcel, of which 283 acres will be kept as a permanent addition and restored to a mix of habitats, includes the primary groundwater drainage zone into the Refuge's Dore Seep,[7] a 26-acre dedicated Illinois Nature Preserve[8] located near the site's southern end.