How far up from the LI sound is the Ct. river is it navigable by powerboat?

Question

sorry for the poor grammar I should have pre-read my question

Answer 1

It is not a question of "How far up from" LI sound is the CT. River -  as The Connecticut River flows "into" Long Island Sound at Old Saybrook, Connecticut. The River itself is 400 miles long and is tidal up to Windsor Locks, approximately 60 miles up stream from Old Saybrook, CT.  All of which is very beautiful boating & fishing...

It is 69 nm or 79 miles by boat from New Rochelle, NY to the entrance to the mouth of the Connecticut River at Old Saybrook, CT   Weather permitting, you can certainly do it all by power boat - the sound & the river...

In fact, both these areas (LI Sound and the CT. River) are the most popular and highest traffic recreational boating areas in the North Eastern US.

Just google "images" of "Connecticut River" and you will see what awaits your arrival.  I think if I remember correctly (I used to live near there)  - the River alone has something like 70 to a 100 marinas...

Happy & Safe Boating!