Strange, I loaded up the game 3 times as the Allies to check, and each tie, that unit was shown as due to enter NORTH of the river.
The conclusion seems to be that from one game to the other, entry locations can change! Dang!
First time I played, all US units entered from North of the river, and I had sent some engineers to build a bridge there and sent a brigade that way, so I assumed that it would always be the same.But this time I was trying out a different strategy and left that location alone.. Dang sneaky AI!
I checked the manual, and nowhere does it say that there can be multiple entry points, nor that it can change from game to game.