Route 63 begins at Route 116 at the north end of the UMass Amherst campus. It heads eastward for a third of a mile before turning onto Sunderland Road (the old alignment of Route 116) for fifty yards, before turning onto Montague Road. Montague Road passes through the western side of the town of Leverett, crossing the New England Central Railroad tracks before entering Sunderland for a short distance, crossing the tracks again before entering Montague. It meets the northern end of Route 47 south of Montague Center before passing Lake Pleasant and crossing the tracks twice more before crossing the Millers River at Millers Falls, entering the town of Erving.
