Which U.S. National Monument spans 87563 acres of mountains and forestland, and borders a large wilderness area located in Piscataquis County in north-central Maine, United States?
Baxter State Park: Baxter State Park is a large wilderness area permanently preserved as a state park, located in Piscataquis County in north-central Maine, United States. Baxter State Park:  It is in the North Maine Woods region, and the Katahdin Woods and Waters National Monument borders Baxter State Park. Katahdin Woods and Waters National Monument: Katahdin Woods and Waters National Monument is a U.S. National Monument spanning 87563 acre of mountains and forestland in northern Penobscot County,Maine, including a section of the East Branch Penobscot River.
Katahdin Woods and Waters National Monument