If you are looking for a great dog friendly state park to visit with the family, take a look at Willard Brook Sate Park on Rte 119 between Townsend and Ashby MA. The park sits on over 2500 acres with trails, rivers and a great area to swim. Dogs on leashes are welcome and there are several areas with picnic tables and grills some along the river.

The trails are extensive and there is great scenery along the way inlcuding a gorgeous waterfall! The brook was widened and sand was brought in to make a nice swimmng area and there are also bathroom facilities.

Here's the state link for more information:

http://www.mass.gov/dcr/parks/northeast/wilb.htm