National Park Service LogoU.S. Department of the InteriorNational Park ServiceNational Park Service
National Park Service:  U.S. Department of the InteriorNational Park Service Arrowhead
Isle Royale National Park A canoer paddles through the fog on the northshore of Isle Royale.
view map
text size: largest larger normal
printer friendly
Isle Royale National Park
Nature & Science
Aerial of the northeast side of Isle Royale.

Nature and ScienceĀ 

In the northwestern portion of Lake Superior is a unique and remote island archipelago. Isle Royale National park preserves 132,018 acres of land that was federally designated as wilderness on October 20, 1976. The park consists of one large island surrounded by over 450 smaller islands; it encompasses a total area of 850 square miles including submerged land, which extends 4 1/2 miles out into the largest fresh water lake in the world. Isle Royale's unique ecosystem led to it being designated an International Biosphere Reserve in 1980.

These isolated islands have only 18 mammal species, compared to over 40 found on the surrounding mainland. Some species have come and gone, often due to human influences. The heavily forested shoreline of Isle Royale appears similar to the mainland's landscape prior to development. Gulls, ravens, and an occasional eagle or osprey dot the skies; squirrels, toads, mice, and spiders move about the forest floor.

The ecological study of wolves on Isle Royale is the longest running large mammal predator-prey study on earth. The park celebrated the study's 50th anniversary in 2008. Research has show that all members of the Isle Royale wolf population have descended from a single female, who arrived during the late 1940s. This intense level of inbreeding has led to a 50 % loss of genetic variability within the population today. Genetic information also suggest that the island's moose population is most closely related to moose in northwestern Minnesota, perhaps challenging the long-held idea that moose swam across the lake to reach Isle Royale. Did humans bring them here?

A venture by foot, canoe or kayak into the park's interior can transport one back thousands of years. Around 11,000 years ago, two miles of ice lay on top of Isle Royale, pressing it down into the earth and sculpting its topography. This same ice sheet gave birth to Lake Superior as well as hundreds of inland lakes, ponds and bogs. The Greenstone Ridge, which forms the backbone of Isle Royale, is thought by many geologist to be a portion of the largest lava flow on earth. All in all, Isle Royale is a fascinating ecosystem to study.


You are exiting the National Park Service website

Thank you for visiting our site.

You will now be redirected to:

We hope your visit was informative and enjoyable.

Areal view of the Rock of Ages Lighthouse on a sunny day with few clouds.

Did You Know?
Rock of Ages Lighthouse contained a second-order Fresnel lens which was the largest sized lens on the Great Lakes. View this magnificent lens at the Windigo Visitor Center.

Last Updated: April 01, 2010 at 11:59 MST