The realization that I knew nothing about Deep River convinced me it was time to do research. Deep River began life as part of the large town of Saybrook.
According to the blog Historic Buildings of Connecticut, Deep River was once home to the ivory trade. The blog mentions the manufacture of ivory combs, but I also remember hearing about the production of pianos. In fact, I think the factory was still there when I was child. There's a nice photo of one factory on Connecticut History Online.
Like all Connecticut River towns, Deep River also likely had some fishing and shipping. At least the images of Connecticut History Online suggest that...
So what else do you know?