Mount Washington has an elevation above sea level of  but has a prominence of about  because it stands that high above its key col — the lowest ground on the ridge line connecting Washington to the higher peaks of the southern Appalachian Mountains. Washington's key col is at the Champlain Canal in New York, the lowest ground on the water divide between the watersheds of the Hudson and Saint Lawrence Rivers.
Mount Washington reaches an altitude above sea level of  but boasts a prominence of about  due to its significant height above its base, which is the lowest point along the ridge connecting Washington to the surrounding Appalachian Mountains. The key col for Washington lies at the Champlain Canal in New York, marking the boundary between the Hudson and Saint Lawrence River watersheds.