Loon Mountain is a mountain in Lincoln, New Hampshire, in Grafton County. It is in the White Mountain National Forest. The 3,065-foot mountain may be best known for Loon Mountain ski resort, which, like most New England mountain resorts, has attempted to expand into an all-season recreation area. It hosts the finals for the northeast circuit of the Mountain Dew Vertical Challenge on the last Saturday of March or first Saturday of April each ski season.