War and Expansion in the US

The idea that it was the fate of the USA to take control of the entire North American continent from coast to coast in order to establish their democratic form of government and spread their civilization

How did the USA gain control of California?

The US Civil War was fought between:

Several southern states seceded from the Union after the election of

What is the term for the period following the Civil War when the nation was rebuilding and reintegrating the southern states to the Union?

In what year was the transcontinental railroad in the US completed?