The centerpiece of the park is a 430-foot-high (130 m), 3-mile-long (4.8 km) steep limestone bluff overlooking Lake Pepin, a natural widening of the Mississippi.

There is a natural limestone arch on the blufftop called In-Yan-Teopa, a Dakota name meaning "Rock With Opening".

Limestone was laid down 500 million years ago as organic sediments settled to the bottom of a shallow sea that covered much of the Midwest.

Much later Glacial River Warren carried torrents of runoff from the melting glaciers of the last ice age.

The park is home to mammalian species of deer, raccoon, coyote, opossum, red fox, woodchuck, beaver and various ground squirrels.

[2] Village sites and burial mounds prove that members of the Hopewell culture were living and dying within the park between 400 BCE and 300 CE.

Fort Beauharnois was intended as a base of operations for trade with the Dakota and for French explorers seeking a route to the Pacific.

[2] The first American settler was James "Bully" Wells, who had a fur trading post near modern Frontenac town by 1840.

His brother Jeptha Garrard was an inventor of flying machines, which were tested, unsuccessfully, from the bluff overlooking the town.

Their holdings more than doubled the next year when 200 acres (81 ha) of Garrard's Bluff were donated by the chairman of an insurance company.

However other residents of Frontenac were fiercely opposed to a park, fearing that heightened visitation would compromise the town's charm and disturb the wildlife.