11 miles (one way) rail trail, extending from Ayer - NH border, going through 4 towns: Ayer, Groton, Pepperell, and Dunstable. Technically this trail extends into Nashua NH. I have done this trail once and it is nice...in fact I don't think I've come across a trail that is not nice ;0)
PARKING: Ayer Center parking lot (60 paved spaces)
Take Rte. 2 east or west to exit 38B, then follow Route 111 north to Ayer Rotary. Go halfway around rotary to Rte. 2A. On Rte. 2A turn right after Ayer Center, take first right on Groton Street to trail parking lot on the right.
The Nashua River Rail Trail travels along a varied landscape, offers numerous scenic overlooks, opportunities to see wildlife and has several resting stops. The trail is particularly attractive during fall foliage season. The Ayer trailhead offers access to commuter rail service between Boston and Fitchburg.