At the base of the beautiful waterfall at this site is a granite pothole 20 feet in diameter. It is believed to have been eroded 15,000 years ago while the North American ice sheet was melting. The Basin has been smoothed by small stones and sand, whirled around by the Pemigewasset River.
Below the Basin is a water-eroded rock formation called the Old Man's Foot.
The Basin can be accessed from the northbound and southbound directions and has its own marked exits. There are picnic tables and walking paths, as well as hiking trails.