Walden Pond, Kettle-hole pond in Concord, United States

Walden Pond is a 64.5-acre kettle-hole pond in Concord, Massachusetts, with a maximum depth of 31 m. Its shore mixes beach sections with steep drops where trails ring the water, and three buildings stand at the main beach on the southeastern shore. The reservation covers 335 acres.

Henry David Thoreau built a cabin on Ralph Waldo Emerson's land on the northern shore and lived there from July 4, 1845, to September 6, 1847. The two years, two months and two days produced Walden; or, Life in the Woods, published in 1854. The site is marked today by granite posts.

The pond's name predates Thoreau and comes from the English place name Walden; his 1854 book Walden made it known worldwide. Visitors can see the granite posts marking his cabin site on the northern shore, and the Concord Museum holds the bed, chair and desk from the cabin.

The site opens early in the morning and closes at sunset, with visitor numbers limited during summer to protect the environment. A loop path around the water takes about an hour and passes through shaded forest sections and open shoreline areas.

The depression formed about 12,000 years ago when glaciers retreated and left large blocks of ice in the ground that later melted. This geological origin explains the unusual depth and round shape of the basin.