There are three ways to get from NYC
up into the great lakes
, and each has different height requirements. All start with the Hudson
1) Champlain canal, Lake Champlain up to the St Lawrence. 17' clearance
2) Eastern Erie Canal + Oswego Canal to Lake Ontario
. 21' clearance (not 17 as stated in another post)
3) Eastern Erie Canal + Western Erie Canal. 15.5' clearance.
Main Page - Erie Canal, Oswego Canal and Champlain Canal Guide
is a good resource for that part of the trip.
As noted in another post, the other tight spot is Chicago, but I think there are two routes with different height restrictions. I don't know the details - haven't been there yet.