Copy link for These Cartographers Screwed Up — But Their Error Preserved Minnesota's Oldest Forest As you walk among the giant pillars of this green cathedral, you might think you're among the redwood trees of California. But those are 1,500 miles (2,500 km) away. No, these are the red and white pines of the "Lost Forty" in Minnesota. This is the largest single surviving patch of old-growth forest in the state and a fair stretch beyond. And it's all thanks to a surveying error. Despite its name, the Lost Forty Scientific and Natural Area (SNA) is actually 144 acres (0.58 km2) in total. Still, it's an easily overlooked part of the Chippewa National Forest, which sprawls across 666,000 acres (2,700 km2) of north-central Minnesota. And that — being easily overlooked — is kind of this area's superpower.