What was one reason freed slaves migrated to western territories?

Freed slaves or the enslaved negroes/black farmers migrated to western territories because the west was new and the United States Agrarian Reform had promised them a free land which is forty (40) acres and a mule under the Homestead Act of 1862. 

These islands/chinampas then provided rich soil for crops with easy access to water. i hope this is correct, im so sorry if its not !