Why did millions of american farm families migrate westward from 1900 to 1910?

Western lands opened up for settlement--the end to Indian War and the passage of the Homestead Act opened new farm land.

New lands opened up after the end of the Indian Wars on the Plains in the 1870s and 1880s. Land could be purchased cheaply and new means of transportation made it easier for families to make the trip. New farming technology such as irrigation systems also made the land more manageable for farming.

The transcontinental railroad provided a means of fast transportation. it cut a 6 month trip into 6 days, created jobs for many people and encouraged immigration. the homestead act played a huge role in western expansion; it allowed settlers to begin a fresh start, and gave them land in exchange for their residence for up to five years and a small fee.