Final answer:
The Charles River is the river that divides Boston from Cambridge. It winds for 80 miles from Hopkinton to Boston Harbor and played a role in the industrial development of the region.
Step-by-step explanation:
The river that divides Boston from Cambridge is the Charles River. It winds for 80 miles from Hopkinton to Boston Harbor. The Charles River played a significant role in the industrial development of the region, powering textile mills in the early 19th century. It is an important landmark in the geography of Boston and Cambridge.