The United States acquired the Oregon territory with the Oregon Treaty in 1846.
Explanation:
The area was jointly occupied after the treaty of 1818 in which the territory was given to both, British and Americans. The Americans knew that region as the Oregon County while the British known it as the Columbia District.
Between the years that both countries held the control jointly the coexistence within the same territory grew intolerable and finally by the year 1846 United State´s president Polk signed the treaty that sets boundaries to both countries in the 49° parallel. Polk did this because at that same time he was engaging in the Mexican- American War and he did not want to fight two wars, especially another one against the British forces.
The title "American Progress" reflects the idea of manifest destiny, the development, and civilization of the American West
The goddess is seen bringing light to the west, which symbolizes the spread of civilization in the frontiers of the west.
The plowing of the field symbolizes the agricultural revolution which significantly expanded the food supply and enabled the citizens to enjoy more pleasant lives.
The trains and the railroads represent the Railroad revolution, which allowed for better transportation systems, communication systems, and a more elevated standard of living.
The painter also contrasts the lighting. The developed side is bright, symbolizing the happiness and prosperity civilizations brings, and the underdeveloped side is dark, suggesting the gloom and hardships of "barbaric" lifestyles.
