Horicon National Wildlife Refuge
The boardwalk across the marsh at Horicon National Wildlife Refuge
Horicon National Wildlife Refuge is a 21,600-acre property surrounding a large part of Horicon Marsh in southeastern Wisconsin. The marsh has its origins in the Green Bay lobe of the northern glaciers during the Wisconsin Glaciation. During its years of advance, the glacier had scraped the surface and created a series of knolls along the way called "drumlins." These drumlins were high points in the landscape and the area around Horicon Marsh has the highest concentration of drumlins in the world. Some of those drumlins are now islands scattered across the marsh area.
When the glaciers retreated, a moraine was created. That moraine held back the meltwaters and caused the formation of Glacial Lake Horicon. Eventually, the Rock River eroded a low spot in the top of the moraine into a free-flowing channel and most of the lake drained away. Over the years layers of clay, silt and peat built up in the former lake basin to form the extensive marshy area we see now.
Arrowheads found in the area point to human habitation as far back as 11,000 years ago. The Mound Builders left dozens of effigy mounds in the area between 800 and 1300 years ago. More recently the area was inhabited by the Ho-Chunk and the Potawatomi. Euro-Americans arrived in the early 1800's and made several attempts to raise and lower the water levels in the marsh. Higher water levels flooded a lot of local farmland, lower water levels exposed peat bogs and let them dry. That led to peat fires that burned for years. Eventually, Wisconsin acquired about 11,000 acres in the southern part of the marsh and established the Horicon Marsh State Wildlife Area. One of the first things they did was construct a dam to raise water levels and more easily regulate water flows in the area. As farmland around the marsh flooded, the US Fish & Wildlife Service acquired it and assembled the northern 21,600 acres of the now marshy area to establish Horicon National Wildlife Refuge.
The majority of the National Wildlife Refuge area is open water and cattail marsh, part of the largest cattail marsh on Earth. The area sees hundreds of thousands of Canada geese pass through in spring and fall, in addition to the more than 300 other species of birds documented on the refuge.
Horicon Marsh State Wildlife Area is also one of the nine units of the Ice Age National Scientific Reserve. Horicon Marsh is also a designated "Globally Important Bird Area" and "Wetland of International Importance."
The main visitor center at Horicon National Wildlife Refuge is on the east side of the refuge and is open daily from 7:30 am to 4 pm year round except federal holidays. The doors are also open in the fall during migration season. The Horicon Marsh Education and Visitor Center is located to the south on the Horicon Marsh State Wildlife Area. The Marsh Haven Nature Center (a private, non-profit education center) is located on the north side of the refuge near Waupun. The refuge itself is open every day, sunrise to sunset and no fees involved. There are several hiking trails, boardwalks and auto-tour routes but the majority of the refuge is closed to the public for most of the year to protect migrating waterfowl. That said, the entire refuge is open to hiking, snowshoeing and cross-country skiing from December 1 to March 15.
Lower photo courtesy of Ryan Hagerty, US Fish & Wildlife Service
Bottom photo courtesy of Wisconsin DNR
Other photos and maps courtesy of the US Fish & Wildlife Service