Green Lakes State Park Professional Guide
Detailed Trail Description from our Guidebook
"The first thing that surprises first-time visitors to Green Lakes State Park is the fact that its name is neither an exaggeration nor a quaint evocation of the surrounding wilderness, but an accurate description of the water: the two lakes found in the park are actually green. The smaller one is Round Lake, an almost perfect circle of emerald water surrounded by heavily wooded slopes. The larger one is Green Lake—about twice its neighbor’s size and also round, but with a long spur that juts out and ends at a sandy beach. Formed by Ice Age glaciers about 14,000 years ago, both are meromictic, a rare type of lake (there are only a few others in the United States) where the surface and bottom waters do not mix. They are small, but astoundingly deep—it’s nearly 200 feet to the bottom of each! These factors, along with the presence of calcium carbonate, cause mainly green light to be reflected by the water, producing the odd but beautiful color that intrigues and delights those who take to the trails along the lakes’ shores."