Aerial view of Ball Mountain Lake, Jamaica, Vt. Ball Mountain Lake is located on the West River, a tributary to the Connecticut River, as part of a network of flood damage reduction projects in the Upper Connecticut River Basin. Construction began in 1956 and was completed in 1961 at a cost of $10.3 million dollars. With a length of 915 feet and a height of 265 feet Ball Mountain is one of the largest earthen dams in New England.