North Bay features one of the last remaining undeveloped stretches of Lake Michigan shore on the Door Peninsula. With nearly one mile of uninterrupted lakeshore, this site offers a range of plant communities that change through time in response to the periodic rise and fall of lake water levels. The site contains many high quality remnant communities including northern sedge meadow, calcareous fen, northern wet, wet-mesic and mesic forest, boreal forests of white spruce and balsam fir, and springs and spring runs. Also present are coastal marshes and a complex of Lake Michigan dunes with associated ridge and swale topography.

From the open waters of the lake, to the coastal marshes and fen, to the lowland forest and surrounding uplands, this area provides critical habitat for many endangered and threatened species including numerous orchids, the federally-threatened dwarf lake iris, and the third largest known breeding population of the federally endangered Hine's emerald dragonfly (Somatochlora hineana). North Bay is also an important spawning area for a majority of Lake Michigan’s whitefish population. Of the estimated 1.2-1.5 million whitefish, approximately 1.1 million spawn in the waters between North Bay and Moonlight Bay in Door county. Outlet streams also provide important habitat for numerous game fish species including northern pike, yellow perch, smallmouth bass, trout, and chinook salmon. Six species of rare or uncommon birds use this area for nesting and foraging including the bald eagle (Haliaeetus leucocephalus) and osprey (Pandion haliaetus).

This site also provides critical habitat for a wide diversity of migratory and nesting waterfowl including bufflehead, redhead, hooded mergansers, and northern pintail and the area is one of the few known nesting sites in Wisconsin of common goldeneye (Bucephala clangula). A wide variety of shorebirds are also known to use the area. North Bay is owned by The Nature Conservancy and The Door County Land Trust. It was designated a State Natural Area in 2002.