The Western Upper Peninsula has a unique geology compared to the rest of Michigan. Ancient bedrock creates surprisingly tall mountains and highlands that trap lakes, swamps, and wetlands hundreds of feet above Lake Superior. Throughout the geologic history of the area, glacial and volcanic events have both carved deep channels and helped confine the waters, eventually leading to rivers draining the land through gorges and over waterfalls. Here is a short list of the major gorges of the area, at least the ones I've had the opportunity of visiting.
Sturgeon River cuts one of the more well-known gorges of this area through the flat, sandy Baraga Plains southwest of L'Anse. This gorge is heavily forested, and good lookouts over it are hard to find. The two highlights of this area include Silver Mountain, an ancient volcanic plug, and Sturgeon River Falls, both located in the Ottawa National Forest. Most of the gorge is simply a deep river valley (three hundred feet near the falls), though there are a few rock cliffs downstream of the falls. The Sturgeon River is a powerful river and cuts another deep channel through slate rock at Canyon River Falls near Alberta.
West and south of the Sturgeon River lays the huge watershed of the Ontonagon River. There are many gorges along its branches and tributaries thanks to the sandy soil and sandstone bedrock. Most of the river's branches are in deep river valleys, but there are a few rocky gorges. I have been to the Onion Creek mouth, a remote set of waterfalls in a cluttered setting, as well as the breathtaking canyon near the Victoria Dam. Both of these are located in sandstone gorges.
North of the Portage lies a number of creeks that flow off of Brockway Ridge to Lake Superior, some falling over six hundred feet. Most of these creeks cut deep cuts into the conglomerate or sandstone rocks, even with minimal normal flow. The most impressive ones include Hammel Creek (Douglass Houghton Falls), Dover Creek (Hungarian Falls), Jacob's Creek, and Silver River.
The Huron Mountain area has plenty of deep river gorges. Both branches of the Huron River go through a gorge, with the West Branch having a series of incredible waterfalls along its route. These gorges have a unique rock structure visible along their steep walls, with angled and blocky chunks of loose walk towering dozens of feet above the rivers. Further to the west of the Huron River is the deep, sharp Slate River gorge with four named drops within. This gorge is lined with angled slate rock and sharp rock outcroppings. These three gorges are surrounded by tall pines and hardwoods and, with the exception of the West Branch of Huron River, far from cabins or any signs of civilization.
A few more river gorges in the Huron Mountains area include the mouth of Cliff River (a sharp, volcanic canyon with a narrow swamp below) near Mt Benison. The Dead River cuts a deep canyon into solid volcanic rock near the McClure Dam with several straight cliffs over fifty feet high. Other notables include the Little Garlic and Carp Rivers near Marquette.