Saddle Ball Mountain is a high summit on the southern ridge of Mount Greylock in northwestern Massachusetts, generally regarded as the state’s second-highest peak. Its name preserves an older tradition in which Mount Greylock was called Saddleback Mountain, with Saddle Ball forming part of the saddle-shaped profile seen from the south. The mountain’s exact highest point has long been debated because maps and elevations differ, though field measurements in 2013 indicated the southernmost of its four outcroppings is highest. Built mainly of Ordovician phyllite and shaped by faulting and glaciation, the upper ridge also supports Massachusetts’s only taiga-boreal or subalpine forest and notable high-elevation bird habitat.