The Detroit River International Wildlife Refuge has officially been recognized by the Old Growth Forest Network, a nonprofit dedicated to identifying and preserving ancient forests across the United States.

The designation applies to 32 acres of old growth forest within Humbug Marsh, a 405-acre site located just south of the refuge’s Trenton, Michigan visitor center. The marsh, which is considered the last undeveloped mile of the Detroit River along the U.S. mainland, contains trees estimated to be 300 years old.

“We know through historical records that the Humbug Marsh property [around 32 acres of it] has been relatively untouched for about 300 years,” said park ranger Alex Gilford.

The Old Growth Forest Network aims to recognize at least one accessible old growth forest per county in Michigan. 

Gilford says visitors to the Detroit River International Wildlife Refuge should look for two types of trees.

“Two tree species that are most notable when you go into that area anyone can see are our oak trees, white oak trees, and our shagbark hickory trees. These are really big diameter trees, they’re really old,” he said. 

The Detroit River International Wildlife Refuge spans from Ecorse to Toledo, managing over 6,200 acres.