According to Wikipedia, Choate Bridge located in Ipswich, Massachusetts (about 30 miles North of Boston) is a stone arch bridge built in 1764 carrying Route 1A/Route 133 over the Ipswich River. It is considered one of the oldest surviving bridges in North America and is more than likely the oldest in Massachusetts.
Lawnstarter has released their annual list of the 150 dirtiest cities in America, with five places in three different New England states making the list.