Map showing the rivers in Saltmarsh and Seaton. 

A discussion on the name of the rivers in Saltmarsh and Seaton led to me sharing this map I found online.  I can't remember where I found it or when but it is nicely done.  It is fairly new as it comports with Ghosts of Saltmarsh.  The map details the coastal area from Redshore to Port Torvin, the Hool Marsh, and the Dreadwood.

http://www.canonfire.com/cf/u/2174/southern_salinmoor.png

....or

https://www.dropbox.com/s/7m5bd1iu3ieljeu/southern_salinmoor.png?dl=0