What fed the american desire to gain colonies and build an empire in the late 1800s and early 1900s?

On of the main things that fed the American desire to gain colonies and build an empire in the late 1800s and early 1900s was "competition with European nations," since during this time many nations in Europe were capitalizing on taking advantage of other nations for their natural resources--especially in Africa. 

They had strained relationships with colonists but good relationships with american indians

If i’m not mistaken your answer should be the freemen’s bureau started them. i really hope i could ! good luck