Actually, New Chicago is the Earth's Capitol city (according to Buck Rodger's in the 25th Century).
I think it's Old Chicago in David Weber's Honor Harrington series....
These are both capital cities in the respective universes.
Saint Lawrence Seaway does seem like a good option, combined with the '38 hurricane hitting. Add in Carol, and it's a mess if Carol also goes that way. New York is very vulnerable if a hurricane comes in wrong...