Question

Which groups benefited most from the United States acquisition port of New Orleans

Answer 1

Ohio River Valley. 
Acquisition of the New Orleans gave the US control of the Mississippi River. That meant farmers in the Ohio River Valley could send their produce down the Ohio River to the Mississippi River and all the way to the Gulf of Mexico.

Answer 2

The Ohio River Valley farmers benefitted the most from the Acquisition of the New Orleans port. It meant the farmers of the Ohio River Valley could ship their produce via the Ohio River down to the Mississippi River then to the Gulf of Mexico.