There are two areas here. This is about the area above the dam. Above the dam it is more like a lake that narrows somewhat as you go upstream. About 2.6 miles in length from where you put in to a shallow point upstream. There is another smaller pond with an island that adjoins the river. It's about a half mile north of the boat ramp, under a small bridge. There is also a picnic table across from the ramp and closer to the dam than the bridge. There is also a rope swing on the west bank about a mile north of the ramp. Slow moving water and very few buildings make this area feel very secluded. You might even see an eagle feeding in this spot.
There is a boat ramp and parking available.
Hotel and fast food 1/4 mile south of the turnpike entrance on Rt 21
From the MA turnpike. Turn right at the light north on Rt 21. Turn right on Chapin St. at the first light. Turn left on East st. at the second light. The go about 2.6 miles to the Red Bridge station boat ramp on left. About 2.7 from the pike.