Walden Pond is a 31-meter-deep (102 ft) lake in Concord, Massachusetts, USA. It is 61 acres (250,000 m2) in area and 1.7 miles (2.7 km) around.
The writer, transcendentalist, and philosopher Henry David Thoreau lived on the shores of the pond for two years starting in the summer of 1845. His account of the experience was recorded in Walden; or, Life in the Woods, and made the spot famous. Concord Museum contains the bed, chair, and desk from Thoreau's cabin.
Managed by the Commonwealth of Massachusetts, Walden Pond State Reservation is a popular swimming destination in the summer where Walden Wednesdays provides an open water swimming alternative. Walden Pond is great for open water swimming in the spring and fall, but the water can get very warm and crowded in the summer. It is a very popular triathlete spot.