What was the main reason the mississippi river was so important to the growing nation?

it offered a way to transport goods from the center of the continent.
it kept the dangerous migrating herds away from populated settlements.
it gave settlers a reason to explore farther to the west of their original settlements.
it maintain a rigid boundary between the colonies and native american populations.

The main reason it was son important was because: it offered a way to transport goods from the center of the continent.  

During the nation's growing era navigation through the Mississippi River became very important since it was cheaper to ship cargo by river than by land over the Appalachian Mountains. This was during most part of the 1800's.  It was up until 1870's that railroads gained more relevance than Mississippi River as the most important commerical transportation mode in Central U.S.

“i think it is very plausible that if there are five votes to end the death penalty, it could be with the people who are on the court right now,” - smith

so basically it is not clearly and consistently imposed