Father Hennepin State Park is located on the southeast shore of Mille Lacs Lake. Visitors enjoy a large sandy beach for swimming, two boat accesses, fishing piers and picnic sites with a panoramic view of the lake. The park's 320 acres include two campgrounds and hiking trails that wind through a hardwood forest and along the rocky shoreline of Mille Lacs. The park's original vegetation was northern hardwoods mixed with marsh areas and pines along the lake. The hardwoods provide shade during the summer and spectacular color in the fall.

Wildlife
Father Hennepin State Park is home to a variety of wildlife. Hawks, ospreys, owls, and eagles are common. The tracks of beaver, raccoon, mink and deer are often seen in the soft earth or snow. Northern pike, walleye, bluegills, sunfish and bass are found in the lake. The aspen stands and small clearings are excellent for ruffed grouse. Squirrels and chipmunks thrive in maple and oak stands. The small ponds and streams provide homes for amphibians and insects, which in turn attract larger fish, birds and mammals.

History
The park is named after Father Louis Hennepin, a priest who visited the area with a French expedition in 1680. Hennepin is not thought to have been in the exact location of the park, but the park is named after him because he was the first to write extensively about the Mille Lacs area. In 1938 land became available along the shore of Lake Mille Lacs, and in 1941 a bill was passed to establish Father Hennepin State Memorial Park.

Geology
About 20,000 years ago, during the peak of the last glacial period, a glacier called the Rainy lobe advanced from the Ontario region through what is now the Boundary Waters Canoe Area and covered most of the Lake Mille Lacs region. As it moved, the Rainy lobe picked up, crushed, and deposited fragments of the underlying bedrock. As the glacier receded, streams of meltwater carried sand gravel from the ice and dropped it in front of the glacier, a deposit called an outwash.

About 15,000 years ago, another glacier, called the Superior lobe, advanced from the Ontario region through the Lake Superior basin and into the area of central Minnesota. It crossed over the outwash that the Rainy lobe had deposited and pushed up the sand gravel into a formation of big elongated hills called a moraine. When the Superior lobe finally receded it left a layer of reddish sediment over this moraine and buried some stranded blocks of stagnant ice. The reddish color comes from iron oxide in the sediment that the glacier eroded from bedrock in the Lake Superior basin.

The enlarged moraine acted as a natural dam, blocking rivers and streams from draining glacial meltwater to the southwest as before. As a result, the meltwater from the receding ice collected behind the moraine and formed the early Lake Mille Lacs. Water from the growing glacial lake spilled over the moraine into the Rum River through an outlet about five meters higher than the present outlet. The original outlet ceased to flow when ice blocks, buried in the moraine, melted enough to open a lower outlet, causing the lake level to drop and create the lake you see today. The lower outlet, which also found drainage via the Rum River, is the one flowing today.

Landscape
Father Hennepin State Park is in the Mille Lacs Uplands subsection. Visitors enjoy the diversity in this park: aspen-birch and mixed hardwood forests, pines, conifer bogs, and swamps. The terminal moraine dam, responsible for the formation of Mille Lacs Lake, is found here.