Directions (via car from Boston): 5.6 miles, 17 minutes
All of the gates except Washington Street Gate mentioned on this page have parking of some sort (usually just along the roads’ shoulders). Thus, this hike can be significantly shorter if one parks on Bussey Street.
From Washington Street Gate, follow Blackwell Path to its intersection with South Street.
Cross South Street (has vehicular traffic) and pass through the South Street Gate onto a wide paved pathway.
After a short distance, bear left at a split onto Hemlock Hill Road (no vehicular traffic).
Follow Hemlock Hill Road as it winds past various tree species until reaching Bussey Street (has vehicular traffic) at the Bussey Street Gate.
Cross Bussey Street, re-entering the reservation at Peters Hill Gate.
Follow Peters Hill Road (no vehicular traffic) until it come to a T.
Straight ahead is a relatively steep unmarked dirt trail that leads to the top of Peters Hill and a fantastic view. NOTE: At the T, one can also take a right and follow that path uphill to another on the right that leads to the summit. This is slightly longer but a little less steep.
Return along the same route or explore some of the other trails in the arboretum.
Here is a link to a trail map (PDF file). Trail maps are not available at any of the gates specifically mentioned on this page.