Round Mountain, 780 feet (238 m) above sea level, was a peak of the Holyoke Range of traprock mountains located in the Connecticut River Valley of Massachusetts, and part of the greater Metacomet Ridge that stretches from Long Island Sound nearly to the Vermont border. Round Mountain was located mostly within Granby but some land was within the towns of Amherst and South Hadley, Massachusetts. It was traversed by the 110-mile (180 km) Metacomet-Monadnock Trail, but no longer, since the trail has been moved at that point to the north to avoid the quarry.

Round Mountain
Removal of Round Mountain by quarrying. 1989 photo; significantly more rock has since been removed.
Highest point
Elevation	780 feet (238 m) (approximate)
Coordinates	42°18′8.43″N 72°31′30.52″W / 42.3023417°N 72.5251444°W / 42.3023417; -72.5251444
Geography
Location	Granby, Amherst, and South Hadley, Massachusetts.
Parent range	Holyoke Range / Metacomet Ridge
Geology
Age of rock	200 Ma
Mountain type	Fault-block; igneous
Climbing
Easiest route	Metacomet-Monadnock Trail

The mining operation started in 1897 and has all but removed the mountain. Together with Bare Mountain to the west, it formed a feature called the Notch. Within the Notch runs state highway Route 116. Travelers through the road could see mountains on both sides. This is no longer true since the quarry has leveled the earth to the east. Before the road was blasted through this area, a trolley passed through. The notch effect was even greater since the slopes of both mountains came down to the edge of the tracks. The bed of this former trolley way is still visible to the east of the current highway. Before the trolley bed it was a dirt highway, and before that a Native American foot path.