This area was called the USA. If this does not answer your question, please rephrase it.
the eastern border of the Louisiana territory is the Mississippi River
The Atlantic Ocean.
eastern is the Mississippi river and the west is the rocky mountains
The eastern border of the United States was still the Atlantic Ocean, but after the Louisiana Purchase in 1803, the western border wasn't well defined. We bought the place from France, and even the French weren't entirely sure what they were selling, or what we were buying. Nominally, the Louisiana Purchase included all of the land drained by the Mississippi River, so the western border should have been the Rocky Mountains and the Continental Divide.
The Mississippi River and the Rocky Mountains.
The eastern border of the United States was still the Atlantic Ocean, but after the Louisiana Purchase in 1803, the western border wasn't well defined. We bought the place from France, and even the French weren't entirely sure what they were selling, or what we were buying. Nominally, the Louisiana Purchase included all of the land drained by the Mississippi River, so the western border should have been the Rocky Mountains and the Continental Divide.
The Southern and Eastern region of the United States.
The Mississippi River and the Rocky Mountains.
The Mississippi River and the Rocky Mountains.
The east was bounded by the Mississippi and the West ( andSouth) by the Missouri River.
Between the Atlantic ocean and the Mississippi river
East in Mississippi River and West in Rocky Mountains