This gave 160 acres of land to new settlers out on the great plains so long as they "improved it.

The Homestead Act of 1862 gave 160 acres of land in the Great Plains in the western United States.  The law was signed on May 20, 1862, by  President Abraham Lincoln. The Homestead Act encouraged migration and opened up settlements to any American, including freed slaves, to own, use and improve the land.

The law required that the new settlers will have to pay a minimal filing fee and to live continuously on the land for five years for them to receive full ownership of the land.

By 1865 (the end of the Civil War), there were 15,000 homestead claims that have been established, with more following in the subsequent years.

the histogram that represents the data with the largest spread is data set b