The invention of the steel plow made it possible to farm the hard prairie sod of the Great Plains. The passage of the Homestead Act of 1862 offered free land to settlers who agreed to live on and improve it for at least five years. The completion of the transcontinental railroad in 1869 provided a cheap and easy way for settlers to travel to the West. These three factors combined to encourage millions of Americans to move to the West and settle the frontier.