Which feature formed the eastern boundary of the louisiana purchase

mississippi river

rocky mountains

british canada

new spain

Mississippi River

Explanation:  The EASTERN boundary of the Louisiana Purchase was the Mississippi River.  The WESTERN boundary would be the Rocky Mountains.

map scale refers to the relationship (or ratio) between distance on a map and the corresponding distance on the ground. for example, on a 1: 100000 scale map, 1cm on the map equals 1km on the ground.