It flows approximately 3 km (2 mi).
[2] The river is formed in Exeter from the confluence of two unnamed streams (one leading from Millbrook Pond and one leading from Money Swamp Pond).
From there, it flows to Rathbon Pond, then into West Greenwich where it converges with the Nooseneck River to form the Big River.
Congdon Mill Road in West Greenwich is the only crossing over the Congdon River due to its short length.
The Congdon River has no named tributaries, though it has many unnamed streams which also feed it.