Delaware & Raritan Canal State Park
The D&R Canal path is a vast trail system that’s flat, but far from boring. Watch rowers gliding by on Lake Carnegie and catch views of the landscape George Washington saw during his famous crossing of the Delaware River. The route is well-maintained, and the mileage well-marked. There’s parking up and down the course, so you can run a loop or an out-and-back.
Sourland Mountain Preserve
The preserve is a bit further from Princeton, but in exchange for a 20-minute drive you’ll get a more technical route with hills, boulders, and a challenge for the ambitious trail runner. If you’re more inclined to a slower pace, take time to look around and you might spot birds, deer, or even the occasional bear. In the middle of the preserve, it gets a little tough to believe you’re in New Jersey.
On a sweltering summer day, the trails owned by the Institute of Advanced Study offer a shady running route. There are criss-crossing trails that let you switch it up, and a good mix of well-maintained trail surfaces. Park at the Princeton Battlefield if you want to start and end your run in the woods.
If you’re looking for something a bit more rugged, Witherspoon Woods offers single-track trails with winding uphills, creek crossings, and wooden boardwalk crossings through marshland. The views are beautiful, especially around sunrise and sunset. Best place to park is in the large lot off Mountain Avenue.