Walden Pond is a lake in Concord, Massachusetts in the United States. A famous example of a kettle hole, it was formed by retreating glaciers 10,000–12,000 years ago. The pond is protected as part of Walden Pond State Reservation, a state park and recreation site managed by the Massachusetts Department of Conservation and Recreation. The reservation was designated a National Historic Landmark in 1962 for its association with the writer Henry David Thoreau (1817–62), whose two years living in a cabin on its shore provided the foundation for his most famous work, Walden; or, Life in the Woods.