Rivers can flow in any compass direction, a river will always flow downhill.
north
the Nile river flows north The Nile does flow north, but it isn't in the US. St. John's River (FL), Willamette River (OR) and the Monongahela River (VA) are the three US rivers that flow north.
north
The Nile River flows from the North
The Nile River flows north.
south to north
South to north.
Into the North Sea
in the north and east
North
The river Trent flows into the North Sea.
It is the Mackensie River.