Walden Pond is a 31-metre-deep (102 ft) lake in Massachusetts. It is 61 acres (250,000 m) in area and 1.7 miles (2.7 km) around, located 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 writer, transcendentalist, and philosopher Henry David Thoreau lived on the shores of the pond for two years starting in the summer of 1845.