Final answer:
The Homestead Act of 1862 was the key legislation that enabled settlers to claim 160 acres of land in the Great Plains for a small fee, provided they improved and lived on it for five years.
Step-by-step explanation:
Homestead Act of 1862
The legislation that helped American citizens, or those aspiring to become citizens, to travel west to the Great Plains and settle with an allocation of 160 acres of land for a small fee, was the Homestead Act of 1862. This act required settlers to live on the property for five years and improve it by cultivating fields, building homes, or other utility buildings.
The federal government provided this opportunity not only to spur the movement to the west but also to support the agricultural output during the Civil War. The act was one of several incentives introduced by the Republicans in Congress to encourage a 'free soil' mentality, deterring the expansion of slavery into new western territories.
Under the Homestead Act, any head of household, or individual over the age of twenty-one, could lay claim to these lands. This included unmarried women who were given the same rights in this respect. The aim was to foster an environment where the independent farmer could thrive, contributing to the overall growth and self-sustainability of the nation.