Katahdin Woods and Waters National Monument in northern Maine protects 87,563 acres of mountains, forests, and part of the East Branch Penobscot River east of Baxter State Park. Established in 2016 after years of land purchases and debate, it preserves both North Woods wildlife habitat and a landscape with deep human history. The Penobscot Nation lived here for more than 11,000 years, and by the 19th century the region was being logged while also serving travelers bound for Katahdin, including Elizabeth Oakes Smith, Henry David Thoreau, and Theodore Roosevelt. Its geology spans hundreds of millions of years, and the monument has since brought growing visitation and local economic benefits.