During the American Civil War, the federal United States government passed the Homestead Act offering free land for those who could "prove up" their claims by living on the land and farming it for a prescribed number of years. Settlers on the newly opened Great Plains found there were not enough trees to build familiar log cabins. As shelter was essential, the settlers utilized ribbons of the thick prairie sod cut from the land. The strip could be cut into two foot sections, four to six inches deep, to make an almost perfect building block with good insulating properties.