Immigration in the late 19th century in the US was the highest immigration numbers of all time. As nationalist movements in Europe pushed people out, the fast growing industrialization pulled people into the US. Immigrants began coming from Eastern and Southern Europe for the first time bringing many Catholics, Jews, and even Muslims in addition to many languages and cultures not known in the US. These groups created ethnic communities in cities where their language and culture could continue. Americans reacted in one of two ways: nativism or reform.
The nativists claimed to be the "native" Americans focused on racial issues and white "native" Americans being the rightly members of the United States.
Reformers worked to assimilate immigrants into society providing education, jobs, and cultural training. The most famous of which was the Hull House in Chicago run by Jane Addams.