The American Frontier

Here are some of the websites I recommended you check

- Why Americans went west? (clear, short with map and pictures) read this

- Pioneers, trails, Native Americans and outlaws, the Homestead Act: read this

- The Transcontinental Railroad: read this

- The End of the Frontier (a very good essay to read, clear and well organized) read this

American Progress by John Gast, 1872