What was the primary reason for the rapid settlement of the Great Plains in the late 1800s?

The primary reason for the rapid settlement of the Great Plains in the late 1800s was the law that Congress passed allowing individuals to claim public land through the process of homesteading. This legislation, particularly the Homestead Act of 1862, provided an opportunity for settlers to acquire parcels of land—typically 160 acres—provided they cultivated it and resided on it for a certain period of time. This act incentivized countless families and individuals by offering an affordable means to own land and start anew, thus promoting westward expansion effectively. The promise of land ownership was particularly appealing during a time when many were seeking new economic opportunities or escaping challenging conditions in the East.

The other options reflect different aspects of land management and settlement but do not encapsulate the core driver of mass settlement like homesteading did. For example, while policies regarding land sales existed, they were not the main catalyst for individual settlers flocking to the Great Plains. Speculation by larger landholders and the interactions with Native American lands similarly did not directly encourage the broad-based, grassroots settlement that homesteading facilitated. Instead, the homesteading law was a critical factor that democratized access to land and propelled the settlement movement during this era.