The bedrock ridges of the Keweenaw Peninsula and of Isle Royale are both part of the Lake Superior syncline, which extends from northern Wisconsin to the tip of the Keweenaw Peninsula of Michigan. Climatic data are not available for Isle Royale.
Fog occurs commonly.
The Lake Superior shoreline consists of rugged volcanic bedrock. Copper-rich lava flows were extensively mined. Linear bedrock ridges and narrow wetlands characterize most of the island, while thin, rocky till covers the southwestern end. Streams on the island are small. Bedrock is at the surface over most of the island.