I have looked through a few of my books relating to the period (1850) and I
haven't come up with anything as conclusive as I'd liked to have.  The Black
Ball packets carried passeners also.  So it appears that the East River piers
served both cargo and passengers.

As far as why use the North River it is my understanding that piers were
established on the North River because it was deeper.   The East River had the
preferred conditions for docking and the original docks were established
there.  But as steamships were bigger and needed deeper slips things moved to
the North River.

However I have found no confirming reference that the SS United States was
actually docked on the North River.  However, in checking an 1860 map of
Manhattan I have found a solitary North River slip labeled "Liverpool".
Unfortunately, more then that I cannot offer.

Jim Maguire
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