Influx of immigrants during different time periods through main ports of entry (Ellis Island, New York & Angel Island, California) during the late 19th and early 20th centuries. This influx came from economic issues and conflict within their home country.
As immigrants moved into the Northeast, housing and land availability issues emerged.
As population increased, pollution and sanitation became major issues in newly industrialized cities.
As population grew cities became overcrowded and quality of life suffered as a result.
A series of federal land grants encouraged settlers to move west into the Great Plains. These land grants greatly contributed to settlement of this region. *