no
No, they formed the eastern boundary, in the form of the continental divide.
yes
continental continental convergent boundary
cascade range, klamath mountains, rocky mountains
yes
no
The Oregon Trail- Megan
the N. platte
eastern is the Mississippi river and the west is the rocky mountains
The three trails that crossed the Rocky Mountains at South Pass were called the Mormon, Oregon, and the California trails.
The Rocky mountains run right through Oregon so it certainly isn't flat. There are some hills.
The Louisiana Purchase and Oregon are divided by the Rocky Mountains.