Geology

The Bad River originates in Caroline Lake in east-central Ashland County and runs a meandering course northward to empty into Lake Superior.

About four miles north of Mellen, the river plunges across an outcropping of resistant rock through which it has been cutting a path for millions of years. The result is a spectacular piece of scenery that today is surrounded by Copper Falls State Park.

The 29-foot Copper Falls marks the first drop of the Bad River as it flows through about two miles of steep-walled canyons of awesome and rugged splendor. Downstream, Tylers Forks of the Bad River joins the main branch of the river by plunging into the canyon over Brownstone Falls. On either side of the swift-flowing water, the walls of the gorge rise 60 to 100 feet. The falls, the rivers and the rock walls add up to a breathtaking and exceptional scenic experience.

There are 8.5 miles of river in the park. One-half mile of river is closed to public access due to its high erosion potential and its value as a unique scenic resource for future generations. This scenic area is easily seen by using established park trails. We appreciate your cooperation in protecting this resource by not hiking or climbing in this one-quarter-mile closed area.

Bridges and vistas

Starting at the log footbridge which spans the river at the falls is a self-guided nature trail that leads to observation points overlooking splendid vistas.

The first trails and bridges were built in 1920 and 1921 by the returning veterans of World War I. In the late 1930s, Civilian Conservation Corps (CCC) and the federal Works Progress Administration (WPA) work programs put thousands of otherwise jobless men to work at a wide variety of public building, park development and conservation projects. Building on that initial contribution, the Department of Natural Resources has continued to provide further development aimed at allowing public use while preserving the matchless natural beauty of the park.

How the falls were made

Eons ago, greenstone and granite mountains stood in northern Wisconsin. They were then worn down to a rolling, rock plain. The plain in the Lake Superior region downwarped and was covered by an ancient sea. Streams on the surrounding dry land carried sand, gravel and mud to the sea where they became thick sea bottom sediments. Iron-rich waters from deep in the earth were forced into the sediments forming this region's valuable iron ores.

Next, thousands of cubic miles of lava oozed from deep fissures where Lake Superior now lies. The lava spread in all directions, building layer upon horizontal layer and reaching a thickness up to 60,000 feet. You can see the lava at the park. So much lava was ejected that the earth's crust sagged, forming the Lake Superior basin.

As the basin settled, streams carried into it sand, boulders and mud. These sediments hardened into sandstones, conglomerates and shales, respectively. Look at Devil's Gate for the peanut brittle-like conglomerate rock. As the Lake Superior basin slowly settled downward, the hardened lava and rock layers angled steeply downward to the north and northwest. Some layers fractured, other layers slid over their neighbors and, in general, great changes took place, leaving these layers standing almost on edge in what's now the park!

The Bad River and Tyler's Fork of the Bad River, not to be denied access to Lake Superior, cut down through the rock layers and carved their present course over the last 200 million years.

Then, during the last one million years, giant glaciers invaded Wisconsin, coming from Canada. As the last glacier melted, it dropped granite boulders and other glacial debris over the entire park, veneering it with sand, mud and rock from Canada. It deposited the thick red clays seen in the high banks near the concession stand. Just a few thousand years ago, Lake Superior held so much water that it was high enough to leave old beach lines in Copper Falls State Park.

From the concession stand downstream, the Bad River flows on black lava and plunges over beautiful Copper Falls. It continues on black lava to its junction with Tyler's Fork. This river also flows on black lava, which supports the Tyler's Fork Cascades and plunges over a red lava ledge to join the Bad River at Brownstone Falls.

From here, the Bad River flows in a deep gorge it cut into red lava, then cuts through the conglomerate rocks at Devil's Gate and then through a narrow band of black shale. The river then meets deep layers of sandstone and shale, makes a 180-degree arc in thick red clays and cuts back into the sandstone and shale layers.

Because of all the rock types involved and their varying hardness and coloration, the gorges and falls make this park one of the most beautiful of Wisconsin's state parks.