From the years 1803 to 1848, United States of America expanded its territories west.
Manifest destiny
![Picture](/uploads/9/5/2/4/9524546/8296684.jpg?1320321907)
Manifest destiny is the reason Americans moved west. They thought that they had to move west because it was inevitable they were going to take that land anyway.the move west created money for the U.S. from the animal fur and the gold that was in California and Oregon. also int he move est for the land the Americans pushed the Indians from their land and took it for the resources.
The Monroe Doctrine
The Monroe Doctrine was an American diplomatic decision which greatly influenced the world and the way it has developed to present day. It was a policy initiated by President James Monroe which aimed to limit European expansion into the Western Hemisphere. Monroe proclaimed, "The American continents, by the free and independent condition which they have assumed and maintain, are henceforth not to be considered as subjects for future colonization by any European powers." The US accepted the responsibility of being the protector of independent Western nations and affirmed that it would steer clear of European affairs. The US believed that the Western Hemishpere belonged to them and Europe cannot interfere.